#include <bits/stdc++.h>
#define rep(i, ss, ee) for (int i = ss; i < ee; ++i)
using namespace std;
using ull = unsigned long long;

int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);

  ull N,M;
  cin >> N >> M;
  ull ans = ((N/M) / 1000) * 1000;
  cout << ans << endl;
  getchar();
}