#include<bits/stdc++.h>
using namespace std;
using ll=long long;

ll power(ll a,ll k){
  ll res=1;
  while(k--){
    res*=a;
  }
  return res;
}

int main(){
  ll h,a;
  cin>>h>>a;
  ll num=h;
  ll k=0;
  while(num){
    k++;
    num/=a;
  }
  cout<<power(2,k)-1<<endl;
}