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());
		int people=Integer.parseInt(sc.nextLine());
		int baka=(int)(money/people);
		int aho=(int)(baka%1000);
		System.out.println(baka-aho);
	}
}