#include <iostream>
#include <vector>
using namespace std;
using ll = long long;
template <class T>
using V = vector<T>;
template <class T>
using VV = V<V<T> >;
const ll inf = 1000000000000000000;


VV<ll> prime_factorize(ll n) {
	VV<ll> prime = {};
	ll f = 2;
	while (f * f <= n) {
		if (n % f == 0) {
			n /= f;
			ll cnt = 1;
			while (n % f == 0) {
				n /= f;
				cnt++;
			}
			prime.push_back({ f,cnt });
		}
		else {
			f++;
		}
	}
	if (n != 1) {
		prime.push_back({ n,1 });
	}
	return prime;
}

ll legendre(ll N, ll K, V<ll>& p) {
	ll R = N - K;
	ll cnt = 0;
	while (N) {
		N /= p[0];
		cnt += N;
	}
	while (K) {
		K /= p[0];
		cnt -= K;
	}
	while (R) {
		R /= p[0];
		cnt -= R;
	}
	return cnt / p[1];
}

int main(void) {
	ll N, K, M;		cin >> N >> K >> M;

	VV<ll> prime = prime_factorize(M);
	ll ans = inf;

	for (auto& p : prime) {
		ans = min(ans, legendre(N, K, p));
	}

	cout << ans << endl;
	return 0;
}