#include <iostream>
#include <vector>
#include <cmath>
#include <map>
#include <set>
#include <iomanip>
#include <queue>
#include <algorithm>
#include <numeric>
#include <deque>

using namespace std;

map<long long, long long> prime;

void prime_factor(long long n){
    long long m = n;

    if (n % 2 == 0){
        while(n % 2 == 0){
            prime[2]++;
            n /= 2;
        }
    }

    for (long long i = 3; i*i <= m; i+=2){
        if (n % i == 0){
            while(n % i == 0){
                prime[i]++;
                n /= i;
            }
        }
    }

    if (n != 1){
        prime[n]++;
    }
}

using ll = long long;

//X!がpで何回割り切れるか？
ll count(ll X, ll p){
    ll cnt=0, q=p;
    while(X/q > 0){
        cnt += X/q;
        if (q <= X/p) q *= p;
        else break;
    }
    return cnt;
}

int main(){

    long long N, K, M, cnt, ans=1e18;
    cin >> N >> K >> M;
    prime_factor(M);

    for (auto [x, y] : prime){
        cnt = count(N, x) - count(K, x) - count(N-K, x);
        ans = min(ans, cnt/y);
    }

    cout << ans << endl;

    return 0;
}