#include <bits/stdc++.h>
using namespace std;

int64_t count(int64_t n, int64_t p)
{
    if (n == 0)
    {
        return 0;
    }
    return n / p + count(n / p, p);
}

int main()
{
    int64_t n, k, m;
    cin >> n >> k >> m;
    map<int64_t, int64_t> primes;
    for (int64_t i = 2; i * i <= m; i++)
    {
        while (m % i == 0)
        {
            primes[i]++;
            m /= i;
        }
    }
    if (m > 1)
    {
        primes[m]++;
    }
    int64_t ans = 1e9;
    for (auto &&[p, c] : primes)
    {
        ans = min(ans, (count(n, p) - count(k, p) - count(n - k, p)) / c);
    }
    cout << ans << endl;
    return 0;
}