#include <bits/stdc++.h>
using namespace std;

typedef long long ll;

signed main(){
  ll N, M; cin >> N >> M;
  N = N / 1000;
  N %= M;
  if( N == 0 )
    cout << 1 << endl;
  else
    cout << N * ( N - 1 ) / 2 << endl;
  return 0;
}