#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (n); i++)
using ll = long long;
using vll = vector<ll>;
using vi = vector<int>;
using vvi = vector<vector<int>>;
using vvll = vector<vector<ll>>;
const ll inf = 1e16;
const ll md = 1000000007;

int main() {
  ll n,m;
  cin >> n>>m;
  ll ans=n/1000/m*1000;
  cout<<ans<<endl;
  return 0;
}