E1:     C1 CALL pred queens_rep.main/2-0 (cc_multi) queens_rep.m:18
mdb> echo on
Command echo enabled.
mdb> context none
Contexts will not be printed.
mdb> goto 9
      E2:     C2 DISJ pred queens_rep.qdelete/3-0 (nondet) c2;d1;
mdb> up
Ancestor level set to 1:
   1  pred queens_rep.qperm/2-0 (nondet)
mdb> up 2
Ancestor level set to 3:
   3  pred queens_rep.main/2-0 (cc_multi)
mdb> level
Ancestor level set to 0:
   0  pred queens_rep.qdelete/3-0 (nondet)
mdb> print
qdelete(_, [1, 2, 3, 4, 5], _)
mdb> continue -n -S
[1, 3, 5, 2, 4]