cs numbnut with a /math/ q here,

im using this function:
>int mpz_probab_prime_p (const mpz_t n, int reps)
https://gmplib.org/manual/Number-Theoretic-Functions


and i'm wondering about the reps.
how many do i need?
if i don't care for false positives at all,
and if i want to be sure it's a prime.