fMarked_fgxf(g(x))g(g(f(x)))f(g(x))g(g(g(x)))f(g(x))g(g(f(x)))f(g(x))g(g(g(x)))Marked_f(g(x))Marked_f(x)f(g(x))g(g(f(x)))f(g(x))g(g(g(x)))Marked_f(g(x))Marked_f(x)Marked_f1Marked_f(g(x))Marked_f(x)f(g(x))g(g(f(x)))f(g(x))g(g(g(x)))