def count_p_in_factorial(n, p):
    count = 0
    while n > 0:
        n = n // p
        count += n
    return count

N, K, M = map(int, input().split())

# Factorize M
factors = {}
m = M
i = 2
while i * i <= m:
    while m % i == 0:
        factors[i] = factors.get(i, 0) + 1
        m = m // i
    i += 1
if m > 1:
    factors[m] = 1

min_x = float('inf')

for p, e in factors.items():
    cnt_n = count_p_in_factorial(N, p)
    cnt_k = count_p_in_factorial(K, p)
    nk = N - K
    cnt_nk = count_p_in_factorial(nk, p) if nk != 0 else 0
    v_p = cnt_n - cnt_k - cnt_nk
    x_p = v_p // e
    if x_p < min_x:
        min_x = x_p

ans = min_x if min_x >= 0 else 0
print(ans)