#include <bits/stdc++.h>
typedef long long int ll;
using namespace std;
int main(void) {
  ll H,A;
  cin>>H>>A;
  ll keta=1,ans=0;
  while(H>0){
    H/=A;
    ans+=keta;
    keta*=2;
  }
  cout<<ans<<endl;
}