#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
#define rep(i, n) for (long long i = 0; i < (long long)(n); i++)
#define repn(i,end) for(long long i = 0; i <= (long long)(end); i++)
#define reps(i,start,end) for(long long i = start; i < (long long)(end); i++)
#define repsn(i,start,end) for(long long i = start; i <= (long long)(end); i++)
#define ll long long
#define ld long double
#define print(t) cout << t << endl 
#define all(a)  (a).begin(),(a).end()
// << std::fixed << std::setprecision(0)
const ll INF = 1LL << 60;
 
template<class T> bool chmin(T& a, T b){
 if(a > b){
  a = b;
  return true;
 }
  return false;
}
 
template<class T> bool chmax(T& a, T b){
 if(a < b){
  a = b;
  return true;
 }
  return false;
}
  
ll lpow(ll x,ll n){
  ll ans = 1;
  while(n >0){
    if(n & 1)ans *= x;
    x *= x;
    n >>= 1;
  }
  return ans;
}
 
int main(){
  ll h,a;cin >> h >> a;
  ll cnt = 0;
  ll num = 1;
  while(h > 0){
    h /= a;
    cnt+=num;
    num *= 2;
  }
  cout << cnt << endl;
}