#include <iostream>	//cin, cout
#include <vector>	//vector
#include <algorithm> //sort,min,max
#include <string>	//string
#include <ios>		//fixed
#include <iomanip>	//setprecision
#include <utility> //swap
#include <cstdlib>	//abs(int)
#include <cmath>	//sqrt
#include <sstream>	//stringstream,getline

using namespace std;

int main() {

	long long int N, M;
	cin >> N >> M;

	N = N / 1000;

	cout << (N / M) * 1000 << endl;

	return 0;

}