YES

---- CR(R)
---- Hot decreasingness.
R:
g(f(a())) -> f(g(f(a())))
g(f(a())) -> f(f(a()))
f(f(a())) -> f(a())

C:
g(f(a())) -> f(f(a()))
f(f(a())) -> f(a())

Label:
[g(f(a())) -> f(g(f(a())))] = 0