#include <iostream>
using namespace std;


int main(){
	int N, M;
	int o = 0;
	cin >> N;
	cin >> M;

	for(;;){
		if(1000 * M <= N){
			o += 1000;
			N -= 1000 * M;
		}else {
			break;
		}
	}
	
	cout << o << endl;

	return 0;
}