//Normal

#define _GLIBCXX_DEBUG
#define ll long long
#include <bits/stdc++.h>
using namespace std;
using Graph = vector<vector<int>>;

void print(auto a){
  cout << a;
}

void prints(auto a){
  cout << a << " ";
}

void prints(){
  cout << " ";
}

void printl(auto a){
  cout << a << endl;
}

void printl(){
  cout << endl;
}

void fix(int n){
  cout << fixed << setprecision(n);
}

int siz(string s){
  return (int)s.size();
}

int main(){
  ll N, K; cin >> N >> K;

  ll ng = 0, ok = 1e18;
  while(ng+1 < ok){
    ll mid = (ng+ok)/2;

    N-mid*K < mid ? ok = mid : ng = mid;
  }

  printl(ok);

  return 0;
}