Standard Out:

in clause balance/ooooo(nil,'-'(X,X),'-'(A,B),'-'(A,B),'-'(cons(tuple(nil,'-'(C,C)),T),T)).
  variables have no producer: ["A","B","C","T","X"]

Standard Err:


real	0m0.211s
user	0m0.184s
sys	0m0.020s