#include <bits/stdc++.h> 

using namespace std;
using ll=long long;
using ull=unsigned long long;
using pii=pair<int,int>;

#define INF LONG_MAX
#define MOD1 1000000007
#define MOD2 998244353
#define MOD MOD1
#define rng(a) a.begin(),a.end()
#define rrng(a) a.end(),a.begin()
#define endl "\n"
#define int ll

map<int,int>prime_factor(int x){
    map<int,int>res;
    for(int i=2;i*i<=x;i++){
        while(x%i==0){
          res[i]++;
          x/=i;
        }
    }
    if(x!=1)res[x]=1;
    return res;
}

signed main(){
    ios::sync_with_stdio(false);
    cin.tie(0);

    int N,K,M;
    cin>>N>>K>>M;
    auto p=prime_factor(M);
    int ans=LONG_LONG_MAX;
    for(auto it:p){
        int res=0;
        int m=1;
        for(int i=0;i<it.second;i++){
            m*=it.first;
        }
        int d=1;
        while(true){
            int nd=N/d;
            int nkd=(N-K)/d;
            int kd=K/d;
            res+=nd-nkd-kd;
            if(d>N/M){
                break;
            }
            d*=m;
        }
        ans=min(ans,res);
    }
    cout<<ans<<endl;

    return 0;
}