YES

---- CR(R)
---- Hot decreasingness.
R:
f(a(),b()) -> c()
a() -> a'()
b() -> b'()
c() -> f(a'(),b())
c() -> f(a(),b'())
c() -> f(a(),b())

C:


Label:
[f(a(),b()) -> c()] = 2
[a() -> a'()] = 0
[b() -> b'()] = 0
[c() -> f(a'(),b())] = 1
[c() -> f(a(),b'())] = 1
[c() -> f(a(),b())] = 1