#include <bits/stdc++.h>
const int INF=1<<30;
int main(){
    long long n,a;
    std::cin >> n >> a;
    long long ans=0,count=1;
    while(n>0){
        ans+=count;
        n/=a;
        count*=2;
    }
    std::cout << ans << '\n' ;
}