eq(f0(A),1,[f1(B,C,D),loop_cont_f1(D)],[C=0,B>=2]).
eq(f0(A),1,[f1(B,C,D)],[C=1,B>=2]).
eq(f1(A,B,C),1,[f1(D,B,C)],[1>=D,D+1>=0,E>=2]).
eq(f1(A,B,A),0,[],[B=1]).