#include <iostream>

using namespace std;
int main()
{
	long a, b, c, d = 0;
	cin >> a >> b;
	if ((a / b) % 1000 != 0)	c = a / b - (a / b) % 1000;

	else c = a / b;

	for (long i = 0; i < c/1000; i++) 
	{
		d += 1000;
	}

	cout << d;
	return 0;
}