#include<bits/stdc++.h>
#define rep(i,a,n) for (int i = a;i < n;i++)
#define per(i,n,a) for (int i = n-1;i >= a;i--)
using namespace std;

int main() {
    long long n,m;
    cin >> n >> m;
    cout << (n / 1000)/m*1000 << endl;
}