eq(f1(A),1,[f4(3,B,C),loop_cont_f4(C)],[B=0]).
eq(f1(A),1,[f4(3,B,C)],[B=1]).
eq(f4(A,B,C),1,[f4(3,B,C)],[]).
eq(f4(A,B,A),0,[],[B=1]).