import java.util.*;

public class Main {
    public static void main(String[] args) throws Exception {
        Scanner koko = new Scanner(System.in);
        int w = koko.nextInt();
        int d = koko.nextInt();
        int rw = w;
        long rd = d;
        for(int i=0; i<d; i++){
            if(rd>1){
                int done = (int)Math.floor(rw/(rd*rd));
                rw=rw-done;
                rd=rd-1;
            }else{
                break;
            }
        }
        System.out.println(rw);
    }
}