#include <iostream>
#include <vector>
#include <queue>
#include <utility>
#include <algorithm>
#include <functional>

using namespace std;
typedef pair<int,int> pii;
#define rep(i,x) for(int i=0;i<(int)(x);++i)

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