#include<bits/stdc++.h>
using namespace std;
using ll = long long;
int main(){
    ll H,A;cin >> H >> A;
    //2の何乗までの合計か？
    ll cnt = 0;
    while(H>0){
        H/=A;
        cnt++;
    }
    //cout << cnt << endl;
    //2のcnt-1乗までの合計
    vector<ll>two(cnt);
    two[0]=1;
    for(ll i = 1;i < cnt;i++)two[i]=two[i-1]*2;
    ll sum = 0;
    for(ll i = 0;i < cnt;i++)sum+=two[i];
    cout << sum << endl;
}