0 QTRS
a__f(X, g(X), Y) → a__f(Y, Y, Y) a__g(b) → c a__b → c mark(f(X1, X2, X3)) → a__f(X1, X2, X3) mark(g(X)) → a__g(mark(X)) mark(b) → a__b mark(c) → c a__f(X1, X2, X3) → f(X1, X2, X3) a__g(X) → g(X) a__b → b