#include <bits/stdc++.h>
#define INF 4611686018427387903ll
using namespace std;
using ll = long long;

vector<pair<ll, int> > prime_factorize(ll n){
    vector<pair<ll, int> > ret = {};
    ll f = 2;
    while(f * f <= n){
        if(n % f == 0){
            n /= f;
            int cnt = 1;
            while(n % f == 0){
                n /= f;
                ++cnt;
            }
            ret.push_back({f, cnt});
        }
        ++f;
    }
    if(n != 1){
        ret.push_back({n, 1});
    }
    return ret;
}


ll legendre(ll N, ll K, ll p, int c){
    ll ret = 0;
    ll R = N - K;
    while(N){
        N /= p;
        ret += N;
    }
    while(K){
        K /= p;
        ret -= K;
    }
    while(R){
        R /= p;
        ret -= R;
    }
    return ret / c;
}


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

    vector<pair<ll, int> > primes = prime_factorize(M);
    ll ans = INF;
    for(auto&[p, c] : primes){
        ll x = legendre(N, K, p, c);
        if(ans <= x){
            continue;
        }
        ans = x;
    }
    cout << ans << endl;

    return 0;
}