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

def factorization(n):
    res = []
    for i in range(2, n):
        if i*i>n:
            break
        if n%i==0:
            cnt = 0
            while n%i==0:
                n//=i
                cnt+=1
            res.append([i, cnt])
    if n>1:
        res.append([n, 1])
    return res

def prime_num(N, p):
    res = 0
    while N>p:
        N//=p
        res+=N
    return res

res = factorization(M)
ans = float('inf')
for p, cnt in res:
    ans = min(ans, prime_num(N, pow(p, cnt))-prime_num(N-K, pow(p, cnt))-prime_num(K, pow(p, cnt)))
print(ans)