for (int j = 0; j < 1000; j++) {
s1.getEnvironment().worldPush();
s2.getEnvironment().worldPush();
IntDomainRandom r = new IntDomainRandom(j);
int val = r.selectValue(vs1[0]);
vs1[0].removeValue(val, Cause.Null);
vs2[0].removeValue(val, Cause.Null);
s1.propagate();
p2.propagate(0);