#include <iostream>

long calc(long w,long d){
  long r=w%(d*d);
  r=w-w/(d*d);
  //std::cout << d << " " <<r << std::endl;
  return r;
}

int main(void){
  using namespace std;
  long w,d,r;
  cin >> w >> d;
  r=w;
  for(long i=d;i>1;i--){
    r=calc(r,i);
  }
  cout << r << endl;
  return 0;    
}