import java.util.*;
import java.lang.*;
import java.io.*;

class Main
{
	public static void main (String[] args) 
	{
		// 入力値の読み込み
		Scanner sc = new Scanner(System.in);
		long n = sc.nextLong();
		long m = sc.nextLong();
		
		long nx = n/1000;
		long ans =nx/m*1000;
		
		System.out.println(ans);
	}
}