Negligible function question.

Alteran

There is a question:

In constructing obfuscators for point-functions theory, there is a statement that there exists a polynomial-time computable permutation
[tex]pi : B^n -> B^n[/tex] and a constant c such that for every polynomial s(n) and every adversary A of size s for all sufficiently large n,

[tex] Prob[A(pi(x)) = x] <= S(n)^c/2^n [/tex]

I am trying to prove that
[tex]S^c(n)/2^n[/tex]
where s is a polynomial and c is a constant, is also a negligible function.

Could anyone help me with that?