#include <iostream>
#include <algorithm>
#include <map>
#include <vector>
#include <climits>
#include <string>
#define REP(a,b) for(int a=0; a<(int)b; a++)

using namespace std;


int main(){
long long  int N, M;
  cin >> N >> M;
  N /= 1000;
  cout << N/M*1000 << endl;

  return 0;
}