#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <queue>
#include <cmath>
#include <climits>
#include <iomanip>
#include <set>
#include <map>
using namespace std;
typedef long long ll;
int main(){
    ll n,a;
    cin >> n >> a;
    n = n / 1000;
    cout << n / a * 1000 << endl; 
}