#include <bits/stdc++.h>

using namespace std;
void fast_io() {
    ios::sync_with_stdio(false);
    std::cin.tie(nullptr);
}

int main() {
    fast_io();
    long long n, k, m;
    cin >> n >> k >> m;
    map<long long, long long> pf;
    for (long long i = 2; i * i <= m; i++) {
        while (m % i == 0) {
            pf[i]++;
            m /= i;
        }
    }
    if (m > 1) {
        pf[m]++;
    }
    long long ans = 9e18;
    for (auto [p, v] : pf) {
        long long cnt = 0;
        long long tmp = p;
        while (tmp <= n) {
            cnt += n / tmp;
            if (tmp > n / p) {
                break;
            }
            tmp *= p;
        }
        tmp = p;
        while (tmp <= k) {
            cnt -= k / tmp;
            if (tmp > k / p) {
                break;
            }
            tmp *= p;
        }
        tmp = p;
        while (tmp <= n - k) {
            cnt -= (n - k) / tmp;
            if (tmp > (n - k) / p) {
                break;
            }
            tmp *= p;
        }
        ans = min(ans, cnt / v);
    }
    cout << ans << endl;
}