(GOAL COMPLEXITY) (STARTTERM (FUNCTIONSYMBOLS f0)) (VAR A B C D) (RULES f0(A,B,C,D) -> Com_1(f1(A,B,C,D)) f1(A,B,C,D) -> Com_1(f1(A + B,B + C,C + D,D - 1)) :|: A >= 1 f1(A,B,C,D) -> Com_1(f1(A - 1,B,C,D)) :|: A >= 1 )