Krakovia

import java.math.BigInteger;
import java.util.Scanner;

public class Main {

    public static void main(String [] args)
    {
        BigInteger bi,V,sum,result;

        int N,F,i,test=0;

        Scanner sc = new Scanner(System.in);

        while(sc.hasNext())
        {
            test++;
            N = sc.nextInt();
            F = sc.nextInt();
            V = BigInteger.valueOf(F);

            if(N==0 && F==0)
            {
                break;
            }
            sum = BigInteger.ZERO;
            for(i=1 ; i<=N; i++)
            {
                bi = sc.nextBigInteger();
                sum = sum.add(bi);
            }

            result = sum.divide(V);

            System.out.println(("Bill #"+test+" costs "+sum+": each friend should pay "+result));
            System.out.println();

        }
    }
}