#include<iostream>
#include<string>
#include<queue>
#include<vector>
#include<cassert>
#include<random>
#include<set>
#include<map>
#include<cassert>
#include<unordered_map>
#include<bitset>
#include<numeric>
#include<algorithm>
using namespace std;
typedef long long ll;
const int inf=1<<30;
const ll INF=1LL<<62;
typedef pair<int,ll> P;
typedef pair<int,P> PP; 
const ll MOD=998244353;
const int dy[]={0,1,0,-1};
const int dx[]={1,0,-1,0};

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

    auto divide=[&](ll n,ll k){
        //n!は kで何回割れるか?

        ll res=0;
        while(n>0){
            res+=n/k;
            n/=k;
        }
        return res;
    };

    ll ans=0;
    ans+=divide(N,M);//N!はMで何回割れるか?
    ans-=divide(K,M);//K!はMで何回割れるか?
    ans-=divide(N-K,M);//(N-K)!はMで何回割れるか?

    cout<<ans<<endl;
}