#include <bits/stdc++.h>
#define int long long
#define double long double
using namespace std;
const int MOD = 1000000007;
const int INF = 1e14;
using Graph = vector<vector<int>>;

signed main(){
  int N, M;
  cin >> N >> M;

  int ans = 0;
  for( int i = 1; i*1000*M <= N; i++ ){
    ans = i*1000;
  }
  cout << ans << endl;
}