#include<bits/stdc++.h>
using namespace std;
int n,k;
int chouyan(int many,int give)
{
    if(many<k)return many;
    return many+chouyan((many-many%give)/give,give);
}
int main(){
    cin>>n>>k;
    cout<<chouyan(n,k);
    return 0;
}