import java.util.HashSet;
import java.util.Scanner;
import java.util.Set;

public class Yuki051 {
    public static void main(String[] args) {
        Yuki051 hoge = new Yuki051();
    }

    Yuki051() {
        Scanner scanner = new Scanner(System.in);
        int W = scanner.nextInt();
        int D = scanner.nextInt();
        for (int i = D; i > 1; i--) {
            W -= W / D / D;
        }
        System.out.println(W);
    }

}