0 QTRS
f(x, f(s(s(y)), f(z, w))) → f(s(x), f(y, f(s(z), w))) L(f(s(s(y)), f(z, w))) → L(f(s(0), f(y, f(s(z), w)))) f(x, f(s(s(y)), nil)) → f(s(x), f(y, f(s(0), nil)))