Execution Chart

We display below the execution chart for this examination (boot time has been removed).

Trace from the execution

Formatting '/data/fkordon/mcc2024-input.r478-tall-171620516300353.qcow2', fmt=qcow2 size=4294967296 backing_file=/data/fkordon/mcc2024-input.qcow2 backing_fmt=qcow2 cluster_size=65536 lazy_refcounts=off refcount_bits=16
Waiting for the VM to be ready (probing ssh)
.....................
=====================================================================
Generated by BenchKit 2-5568
Executing tool ltsminxred
Input is CloudDeployment-PT-3b, examination is StableMarking
Time confinement is 1800 seconds
Memory confinement is 16384 MBytes
Number of cores is 4
Run identifier is r478-tall-171620516300353
=====================================================================

--------------------
preparation of the directory to be used:
/home/mcc/execution
total 808K
-rw-r--r-- 1 mcc users 6.7K May 14 13:22 CTLCardinality.txt
-rw-r--r-- 1 mcc users 70K May 14 13:22 CTLCardinality.xml
-rw-r--r-- 1 mcc users 5.0K May 14 13:22 CTLFireability.txt
-rw-r--r-- 1 mcc users 45K May 14 13:22 CTLFireability.xml
-rw-r--r-- 1 mcc users 4.2K May 18 16:42 GenericPropertiesDefinition.xml
-rw-r--r-- 1 mcc users 3.5K Apr 22 14:33 LTLCardinality.txt
-rw-r--r-- 1 mcc users 23K Apr 22 14:33 LTLCardinality.xml
-rw-r--r-- 1 mcc users 2.0K May 19 07:14 LTLFireability.txt
-rw-r--r-- 1 mcc users 15K May 19 18:04 LTLFireability.xml
-rw-r--r-- 1 mcc users 17K Apr 11 15:43 ReachabilityCardinality.txt
-rw-r--r-- 1 mcc users 189K Apr 11 15:43 ReachabilityCardinality.xml
-rw-r--r-- 1 mcc users 8.0K Apr 11 15:42 ReachabilityFireability.txt
-rw-r--r-- 1 mcc users 68K Apr 11 15:42 ReachabilityFireability.xml
-rw-r--r-- 1 mcc users 1.7K Apr 22 14:33 UpperBounds.txt
-rw-r--r-- 1 mcc users 3.7K Apr 22 14:33 UpperBounds.xml
-rw-r--r-- 1 mcc users 6 May 18 16:42 equiv_col
-rw-r--r-- 1 mcc users 3 May 18 16:42 instance
-rw-r--r-- 1 mcc users 6 May 18 16:42 iscolored
-rw-r--r-- 1 mcc users 308K May 18 16:42 model.pnml

--------------------
content from stdout:

=== Data for post analysis generated by BenchKit (invocation template)

The expected result is a vector of booleans
BOOL_VECTOR

FORMULA_NAME StableMarking

=== Now, execution of the tool begins

BK_START 1717179591100

Invoking MCC driver with
BK_TOOL=ltsminxred
BK_EXAMINATION=StableMarking
BK_BIN_PATH=/home/mcc/BenchKit/bin/
BK_TIME_CONFINEMENT=1800
BK_INPUT=CloudDeployment-PT-3b
BK_MEMORY_CONFINEMENT=16384
Applying reductions before tool ltsmin
Invoking reducer
Running Version 202405141337
[2024-05-31 18:19:52] [INFO ] Running its-tools with arguments : [-pnfolder, /home/mcc/execution, -examination, StableMarking, -timeout, 180, -rebuildPNML]
[2024-05-31 18:19:52] [INFO ] Parsing pnml file : /home/mcc/execution/model.pnml
[2024-05-31 18:19:52] [INFO ] Load time of PNML (sax parser for PT used): 114 ms
[2024-05-31 18:19:52] [INFO ] Transformed 859 places.
[2024-05-31 18:19:52] [INFO ] Transformed 1152 transitions.
[2024-05-31 18:19:52] [INFO ] Found NUPN structural information;
[2024-05-31 18:19:52] [INFO ] Parsed PT model containing 859 places and 1152 transitions and 4030 arcs in 222 ms.
Graph (trivial) has 876 edges and 859 vertex of which 252 / 859 are part of one of the 24 SCC in 6 ms
Free SCC test removed 228 places
Structural test allowed to assert that 323 places are NOT stable. Took 28 ms.
Ensure Unique test removed 255 transitions
Reduce redundant transitions removed 255 transitions.
RANDOM walk for 40000 steps (542 resets) in 1917 ms. (20 steps per ms) remains 269/536 properties
BEST_FIRST walk for 403 steps (8 resets) in 8 ms. (44 steps per ms) remains 269/269 properties
BEST_FIRST walk for 404 steps (8 resets) in 10 ms. (36 steps per ms) remains 269/269 properties
BEST_FIRST walk for 404 steps (8 resets) in 9 ms. (40 steps per ms) remains 269/269 properties
BEST_FIRST walk for 403 steps (8 resets) in 11 ms. (33 steps per ms) remains 269/269 properties
BEST_FIRST walk for 402 steps (8 resets) in 11 ms. (33 steps per ms) remains 269/269 properties
BEST_FIRST walk for 403 steps (8 resets) in 9 ms. (40 steps per ms) remains 269/269 properties
BEST_FIRST walk for 403 steps (8 resets) in 9 ms. (40 steps per ms) remains 269/269 properties
BEST_FIRST walk for 404 steps (8 resets) in 9 ms. (40 steps per ms) remains 269/269 properties
BEST_FIRST walk for 403 steps (8 resets) in 7 ms. (50 steps per ms) remains 269/269 properties
BEST_FIRST walk for 403 steps (8 resets) in 10 ms. (36 steps per ms) remains 269/269 properties
BEST_FIRST walk for 404 steps (8 resets) in 9 ms. (40 steps per ms) remains 269/269 properties
BEST_FIRST walk for 403 steps (8 resets) in 8 ms. (44 steps per ms) remains 269/269 properties
BEST_FIRST walk for 403 steps (8 resets) in 8 ms. (44 steps per ms) remains 269/269 properties
BEST_FIRST walk for 404 steps (8 resets) in 17 ms. (22 steps per ms) remains 269/269 properties
BEST_FIRST walk for 404 steps (8 resets) in 7 ms. (50 steps per ms) remains 269/269 properties
BEST_FIRST walk for 404 steps (8 resets) in 6 ms. (57 steps per ms) remains 269/269 properties
BEST_FIRST walk for 404 steps (8 resets) in 8 ms. (44 steps per ms) remains 269/269 properties
BEST_FIRST walk for 403 steps (8 resets) in 12 ms. (31 steps per ms) remains 269/269 properties
BEST_FIRST walk for 402 steps (8 resets) in 12 ms. (30 steps per ms) remains 269/269 properties
BEST_FIRST walk for 404 steps (8 resets) in 7 ms. (50 steps per ms) remains 269/269 properties
BEST_FIRST walk for 402 steps (8 resets) in 11 ms. (33 steps per ms) remains 269/269 properties
BEST_FIRST walk for 404 steps (8 resets) in 6 ms. (57 steps per ms) remains 269/269 properties
BEST_FIRST walk for 403 steps (8 resets) in 8 ms. (44 steps per ms) remains 269/269 properties
BEST_FIRST walk for 404 steps (8 resets) in 10 ms. (36 steps per ms) remains 269/269 properties
BEST_FIRST walk for 403 steps (8 resets) in 8 ms. (44 steps per ms) remains 269/269 properties
BEST_FIRST walk for 404 steps (8 resets) in 13 ms. (28 steps per ms) remains 269/269 properties
BEST_FIRST walk for 404 steps (8 resets) in 6 ms. (57 steps per ms) remains 269/269 properties
BEST_FIRST walk for 402 steps (8 resets) in 9 ms. (40 steps per ms) remains 269/269 properties
BEST_FIRST walk for 403 steps (8 resets) in 7 ms. (50 steps per ms) remains 269/269 properties
BEST_FIRST walk for 404 steps (8 resets) in 6 ms. (57 steps per ms) remains 269/269 properties
BEST_FIRST walk for 402 steps (8 resets) in 7 ms. (50 steps per ms) remains 269/269 properties
BEST_FIRST walk for 404 steps (8 resets) in 10 ms. (36 steps per ms) remains 269/269 properties
BEST_FIRST walk for 404 steps (8 resets) in 6 ms. (57 steps per ms) remains 269/269 properties
BEST_FIRST walk for 403 steps (8 resets) in 11 ms. (33 steps per ms) remains 269/269 properties
BEST_FIRST walk for 403 steps (8 resets) in 9 ms. (40 steps per ms) remains 269/269 properties
BEST_FIRST walk for 400 steps (8 resets) in 7 ms. (50 steps per ms) remains 269/269 properties
BEST_FIRST walk for 403 steps (8 resets) in 6 ms. (57 steps per ms) remains 269/269 properties
BEST_FIRST walk for 403 steps (8 resets) in 15 ms. (25 steps per ms) remains 269/269 properties
BEST_FIRST walk for 404 steps (8 resets) in 6 ms. (57 steps per ms) remains 269/269 properties
BEST_FIRST walk for 401 steps (8 resets) in 6 ms. (57 steps per ms) remains 269/269 properties
BEST_FIRST walk for 404 steps (8 resets) in 6 ms. (57 steps per ms) remains 269/269 properties
BEST_FIRST walk for 404 steps (8 resets) in 6 ms. (57 steps per ms) remains 269/269 properties
BEST_FIRST walk for 403 steps (8 resets) in 7 ms. (50 steps per ms) remains 269/269 properties
BEST_FIRST walk for 404 steps (8 resets) in 6 ms. (57 steps per ms) remains 269/269 properties
BEST_FIRST walk for 404 steps (8 resets) in 8 ms. (44 steps per ms) remains 269/269 properties
BEST_FIRST walk for 403 steps (8 resets) in 8 ms. (44 steps per ms) remains 269/269 properties
BEST_FIRST walk for 403 steps (8 resets) in 9 ms. (40 steps per ms) remains 269/269 properties
BEST_FIRST walk for 402 steps (8 resets) in 6 ms. (57 steps per ms) remains 269/269 properties
BEST_FIRST walk for 403 steps (8 resets) in 7 ms. (50 steps per ms) remains 269/269 properties
BEST_FIRST walk for 403 steps (8 resets) in 6 ms. (57 steps per ms) remains 269/269 properties
[2024-05-31 18:19:53] [INFO ] Flow matrix only has 874 transitions (discarded 23 similar events)
// Phase 1: matrix 874 rows 631 cols
[2024-05-31 18:19:53] [INFO ] Computed 13 invariants in 24 ms
[2024-05-31 18:19:53] [INFO ] State equation strengthened by 1 read => feed constraints.
All remaining problems are real, not stopping.
At refinement iteration 0 (INCLUDED_ONLY) 0/269 variables, 269/269 constraints. Problems are: Problem set: 0 solved, 269 unsolved
At refinement iteration 1 (INCLUDED_ONLY) 0/269 variables, 1/270 constraints. Problems are: Problem set: 0 solved, 269 unsolved
At refinement iteration 2 (INCLUDED_ONLY) 0/269 variables, 0/270 constraints. Problems are: Problem set: 0 solved, 269 unsolved
At refinement iteration 3 (OVERLAPS) 361/630 variables, 12/282 constraints. Problems are: Problem set: 0 solved, 269 unsolved
At refinement iteration 4 (INCLUDED_ONLY) 0/630 variables, 361/643 constraints. Problems are: Problem set: 0 solved, 269 unsolved
Error getting values : (error "ParserException while parsing response: ((s1 0.0)
(s2 0.0)
(s3 0.0)
(s4 0.0)
(s5 0.0)
(s6 0.0)
(s7 0.0)
(s8 0.0)
(s9 0.0)
(s10 0.0)
(s11 0.0)
(s12 0.0)
(s13 0.0)
(s14 0.0)
(s15 0.0)
(s16 0.0)
(s17 0.0)
(s18 0.0)
(s19 timeout
org.smtlib.IParser$ParserException: Unbalanced parentheses at end of input")
Solver is answering 'unknown', stopping.
After SMT solving in domain Real declared 630/1505 variables, and 643 constraints, problems are : Problem set: 0 solved, 269 unsolved in 5049 ms.
Refiners :[Domain max(s): 630/631 constraints, Generalized P Invariants (flows): 13/13 constraints, State Equation: 0/631 constraints, ReadFeed: 0/1 constraints, PredecessorRefiner: 269/269 constraints, Known Traps: 0/0 constraints]
Escalating to Integer solving :Problem set: 0 solved, 269 unsolved
At refinement iteration 0 (INCLUDED_ONLY) 0/269 variables, 269/269 constraints. Problems are: Problem set: 0 solved, 269 unsolved
At refinement iteration 1 (INCLUDED_ONLY) 0/269 variables, 1/270 constraints. Problems are: Problem set: 0 solved, 269 unsolved
At refinement iteration 2 (INCLUDED_ONLY) 0/269 variables, 0/270 constraints. Problems are: Problem set: 0 solved, 269 unsolved
At refinement iteration 3 (OVERLAPS) 361/630 variables, 12/282 constraints. Problems are: Problem set: 0 solved, 269 unsolved
At refinement iteration 4 (INCLUDED_ONLY) 0/630 variables, 361/643 constraints. Problems are: Problem set: 0 solved, 269 unsolved
At refinement iteration 5 (INCLUDED_ONLY) 0/630 variables, 0/643 constraints. Problems are: Problem set: 0 solved, 269 unsolved
At refinement iteration 6 (OVERLAPS) 873/1503 variables, 630/1273 constraints. Problems are: Problem set: 0 solved, 269 unsolved
At refinement iteration 7 (INCLUDED_ONLY) 0/1503 variables, 269/1542 constraints. Problems are: Problem set: 0 solved, 269 unsolved
Solver is answering 'unknown', stopping.
After SMT solving in domain Int declared 1503/1505 variables, and 1542 constraints, problems are : Problem set: 0 solved, 269 unsolved in 5023 ms.
Refiners :[Domain max(s): 630/631 constraints, Generalized P Invariants (flows): 13/13 constraints, State Equation: 630/631 constraints, ReadFeed: 0/1 constraints, PredecessorRefiner: 269/269 constraints, Known Traps: 0/0 constraints]
After SMT, in 10232ms problems are : Problem set: 0 solved, 269 unsolved
Skipping Parikh replay, no witness traces provided.
Support contains 269 out of 631 places. Attempting structural reductions.
Starting structural reductions in REACHABILITY mode, iteration 0 : 631/631 places, 897/897 transitions.
Drop transitions (Empty/Sink Transition effects.) removed 24 transitions
Reduce isomorphic transitions removed 24 transitions.
Drop transitions (Trivial Post-Agglo cleanup.) removed 182 transitions
Trivial Post-agglo rules discarded 182 transitions
Performed 182 trivial Post agglomeration. Transition count delta: 182
Iterating post reduction 0 with 206 rules applied. Total rules applied 206 place count 631 transition count 691
Reduce places removed 182 places and 0 transitions.
Iterating post reduction 1 with 182 rules applied. Total rules applied 388 place count 449 transition count 691
Performed 6 Pre agglomeration using Quasi-Persistent + Divergent Free condition..
Pre-agglomeration after 2 with 6 Pre rules applied. Total rules applied 388 place count 449 transition count 685
Deduced a syphon composed of 6 places in 2 ms
Reduce places removed 6 places and 0 transitions.
Iterating global reduction 2 with 12 rules applied. Total rules applied 400 place count 443 transition count 685
Discarding 47 places :
Symmetric choice reduction at 2 with 47 rule applications. Total rules 447 place count 396 transition count 638
Iterating global reduction 2 with 47 rules applied. Total rules applied 494 place count 396 transition count 638
Ensure Unique test removed 6 transitions
Reduce isomorphic transitions removed 6 transitions.
Iterating post reduction 2 with 6 rules applied. Total rules applied 500 place count 396 transition count 632
Performed 30 Post agglomeration using F-continuation condition.Transition count delta: 30
Deduced a syphon composed of 30 places in 1 ms
Reduce places removed 30 places and 0 transitions.
Iterating global reduction 3 with 60 rules applied. Total rules applied 560 place count 366 transition count 602
Performed 18 Post agglomeration using F-continuation condition with reduction of 36 identical transitions.
Deduced a syphon composed of 18 places in 1 ms
Reduce places removed 18 places and 0 transitions.
Iterating global reduction 3 with 36 rules applied. Total rules applied 596 place count 348 transition count 629
Drop transitions (Redundant composition of simpler transitions.) removed 12 transitions
Redundant transition composition rules discarded 12 transitions
Iterating global reduction 3 with 12 rules applied. Total rules applied 608 place count 348 transition count 617
Free-agglomeration rule applied 36 times with reduction of 6 identical transitions.
Iterating global reduction 3 with 36 rules applied. Total rules applied 644 place count 348 transition count 575
Reduce places removed 36 places and 0 transitions.
Drop transitions (Empty/Sink Transition effects.) removed 26 transitions
Reduce isomorphic transitions removed 26 transitions.
Iterating post reduction 3 with 62 rules applied. Total rules applied 706 place count 312 transition count 549
Drop transitions (Redundant composition of simpler transitions.) removed 14 transitions
Redundant transition composition rules discarded 14 transitions
Iterating global reduction 4 with 14 rules applied. Total rules applied 720 place count 312 transition count 535
Partial Free-agglomeration rule applied 1 times.
Drop transitions (Partial Free agglomeration) removed 1 transitions
Iterating global reduction 4 with 1 rules applied. Total rules applied 721 place count 312 transition count 535
Reduce places removed 1 places and 1 transitions.
Iterating global reduction 4 with 1 rules applied. Total rules applied 722 place count 311 transition count 534
Applied a total of 722 rules in 183 ms. Remains 311 /631 variables (removed 320) and now considering 534/897 (removed 363) transitions.
Finished structural reductions in REACHABILITY mode , in 1 iterations and 193 ms. Remains : 311/631 places, 534/897 transitions.
RANDOM walk for 4000000 steps (75901 resets) in 20295 ms. (197 steps per ms) remains 14/269 properties
BEST_FIRST walk for 4000004 steps (13809 resets) in 3555 ms. (1124 steps per ms) remains 14/14 properties
BEST_FIRST walk for 4000004 steps (13807 resets) in 3552 ms. (1125 steps per ms) remains 14/14 properties
BEST_FIRST walk for 4000001 steps (13821 resets) in 3510 ms. (1139 steps per ms) remains 14/14 properties
BEST_FIRST walk for 4000004 steps (13716 resets) in 3671 ms. (1089 steps per ms) remains 14/14 properties
BEST_FIRST walk for 4000003 steps (13740 resets) in 3641 ms. (1098 steps per ms) remains 14/14 properties
BEST_FIRST walk for 4000002 steps (13925 resets) in 3568 ms. (1120 steps per ms) remains 14/14 properties
BEST_FIRST walk for 4000004 steps (13800 resets) in 3508 ms. (1139 steps per ms) remains 14/14 properties
BEST_FIRST walk for 4000004 steps (13808 resets) in 3538 ms. (1130 steps per ms) remains 14/14 properties
BEST_FIRST walk for 4000004 steps (13857 resets) in 3526 ms. (1134 steps per ms) remains 14/14 properties
BEST_FIRST walk for 4000004 steps (13797 resets) in 3557 ms. (1124 steps per ms) remains 14/14 properties
BEST_FIRST walk for 4000004 steps (13832 resets) in 3592 ms. (1113 steps per ms) remains 14/14 properties
BEST_FIRST walk for 3080626 steps (10563 resets) in 3874 ms. (795 steps per ms) remains 0/14 properties
Able to resolve query StableMarking after proving 538 properties.
FORMULA StableMarking FALSE TECHNIQUES RANDOM_WALK MARKED_SUFFIX_TEST TRIVIAL_UNMARKED_SCC_TEST BESTFIRST_WALK TOPOLOGICAL
Total runtime 29665 ms.
ITS solved all properties within timeout

BK_STOP 1717179621927

--------------------
content from stderr:

+ ulimit -s 65536
+ [[ -z '' ]]
+ export LTSMIN_MEM_SIZE=8589934592
+ LTSMIN_MEM_SIZE=8589934592
+ export PYTHONPATH=/home/mcc/BenchKit/itstools/pylibs
+ PYTHONPATH=/home/mcc/BenchKit/itstools/pylibs
+ export LD_LIBRARY_PATH=/home/mcc/BenchKit/itstools/pylibs:
+ LD_LIBRARY_PATH=/home/mcc/BenchKit/itstools/pylibs:
++ sed s/.jar//
++ perl -pe 's/.*\.//g'
++ ls /home/mcc/BenchKit/bin//../reducer/bin//../../itstools//itstools/plugins/fr.lip6.move.gal.application.pnmcc_1.0.0.202405141337.jar
+ VERSION=202405141337
+ echo 'Running Version 202405141337'
+ /home/mcc/BenchKit/bin//../reducer/bin//../../itstools//itstools/its-tools -pnfolder /home/mcc/execution -examination StableMarking -timeout 180 -rebuildPNML

Sequence of Actions to be Executed by the VM

This is useful if one wants to reexecute the tool in the VM from the submitted image disk.

set -x
# this is for BenchKit: configuration of major elements for the test
export BK_INPUT="CloudDeployment-PT-3b"
export BK_EXAMINATION="StableMarking"
export BK_TOOL="ltsminxred"
export BK_RESULT_DIR="/tmp/BK_RESULTS/OUTPUTS"
export BK_TIME_CONFINEMENT="1800"
export BK_MEMORY_CONFINEMENT="16384"
export BK_BIN_PATH="/home/mcc/BenchKit/bin/"

# this is specific to your benchmark or test

export BIN_DIR="$HOME/BenchKit/bin"

# remove the execution directoty if it exists (to avoid increse of .vmdk images)
if [ -d execution ] ; then
rm -rf execution
fi

# this is for BenchKit: explicit launching of the test
echo "====================================================================="
echo " Generated by BenchKit 2-5568"
echo " Executing tool ltsminxred"
echo " Input is CloudDeployment-PT-3b, examination is StableMarking"
echo " Time confinement is $BK_TIME_CONFINEMENT seconds"
echo " Memory confinement is 16384 MBytes"
echo " Number of cores is 4"
echo " Run identifier is r478-tall-171620516300353"
echo "====================================================================="
echo
echo "--------------------"
echo "preparation of the directory to be used:"

tar xzf /home/mcc/BenchKit/INPUTS/CloudDeployment-PT-3b.tgz
mv CloudDeployment-PT-3b execution
cd execution
if [ "StableMarking" = "ReachabilityDeadlock" ] || [ "StableMarking" = "UpperBounds" ] || [ "StableMarking" = "QuasiLiveness" ] || [ "StableMarking" = "StableMarking" ] || [ "StableMarking" = "Liveness" ] || [ "StableMarking" = "OneSafe" ] || [ "StableMarking" = "StateSpace" ]; then
rm -f GenericPropertiesVerdict.xml
fi
pwd
ls -lh

echo
echo "--------------------"
echo "content from stdout:"
echo
echo "=== Data for post analysis generated by BenchKit (invocation template)"
echo
if [ "StableMarking" = "UpperBounds" ] ; then
echo "The expected result is a vector of positive values"
echo NUM_VECTOR
elif [ "StableMarking" != "StateSpace" ] ; then
echo "The expected result is a vector of booleans"
echo BOOL_VECTOR
else
echo "no data necessary for post analysis"
fi
echo
if [ -f "StableMarking.txt" ] ; then
echo "here is the order used to build the result vector(from text file)"
for x in $(grep Property StableMarking.txt | cut -d ' ' -f 2 | sort -u) ; do
echo "FORMULA_NAME $x"
done
elif [ -f "StableMarking.xml" ] ; then # for cunf (txt files deleted;-)
echo echo "here is the order used to build the result vector(from xml file)"
for x in $(grep '' StableMarking.xml | cut -d '>' -f 2 | cut -d '<' -f 1 | sort -u) ; do
echo "FORMULA_NAME $x"
done
elif [ "StableMarking" = "ReachabilityDeadlock" ] || [ "StableMarking" = "QuasiLiveness" ] || [ "StableMarking" = "StableMarking" ] || [ "StableMarking" = "Liveness" ] || [ "StableMarking" = "OneSafe" ] ; then
echo "FORMULA_NAME StableMarking"
fi
echo
echo "=== Now, execution of the tool begins"
echo
echo -n "BK_START "
date -u +%s%3N
echo
timeout -s 9 $BK_TIME_CONFINEMENT bash -c "/home/mcc/BenchKit/BenchKit_head.sh 2> STDERR ; echo ; echo -n \"BK_STOP \" ; date -u +%s%3N"
if [ $? -eq 137 ] ; then
echo
echo "BK_TIME_CONFINEMENT_REACHED"
fi
echo
echo "--------------------"
echo "content from stderr:"
echo
cat STDERR ;