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

C =10 ** 6 + 1
dat = [0] * C
prime = dict()
for i in range(2,C):
    if dat[i] == 0:
        for j in range(2 * i,C,i):
            dat[j] = 1
        if M % i == 0:
            count = 0
            while M % i == 0:
                count += 1
                M //= i
            prime[i] = count
if M != 1:
    prime[M] = 1
_min = 10 ** 9
def count(t,p):
    ans = 0
    i = p
    while t // i:
        ans += t // i
        i *= p
    return ans
for p in prime:
    a = count(N,p)
    b = count(K,p)
    c = count(N-K,p)
    d = a - b - c
    e = d // prime[p]
    if e < _min:
        _min = e
print(_min)