#define _CRT_SECURE_NO_WARNINGS
#define _USE_MATH_DEFINES
#include <iostream>
#include <map>
#include <list>
#include <cstdio>
#include <cmath>
#include <cstring>
#include <string>
#include <vector>
#include <algorithm>
#include <utility>
#include <queue>
#include <iomanip>
#define INF 1050000000

using namespace std;


int main(void)
{
	long long n, m;

	cin >> n >> m;
	
	cout << ((n / m) / 1000) * 1000 << endl;
		
	return (0);
}