import java.util.Scanner;
public class Main{
	public static void main(String args[])throws Exception{
		Scanner sc=new Scanner(System.in);
		long money=Long.parseLong(sc.nextLine());
		long people=Integer.parseInt(sc.nextLine());
		long baka=(money/people);
		long aho=(baka%1000);
		System.out.println(baka-aho);
	}
}