#include<iostream>

using namespace std;
#define int long long

signed main(){

   int N, D;
   cin>> N>> D;

   int ans=0;
   int n=N;
   while(1){
      ans+=(n/D);
      int mod=n%D;
      if(mod==0){
         break;
      }else{
         n=N+mod;
      }
   }

   cout<< ans-1<< endl;

   return 0;
}