0 QTRS
a(b(x)) → b(a(a(x))) b(c(x)) → c(b(b(x))) c(a(x)) → a(c(c(x))) u(a(x)) → x v(b(x)) → x w(c(x)) → x a(u(x)) → x b(v(x)) → x c(w(x)) → x