#include<bits/stdc++.h>
using namespace std;


string stringdiv(string s,int c)
{
    string ans;
    int id=0;
    int num=s[id]-'0';
    while(num<c)
        num=(num*10)+(s[++id]-'0');
   while(s.size()>id)
   {
       ans+=((num/c)+'0');
       num=(num%c)*10 + (s[++id]-'0');
   }
    if(ans.length()==0)
        return "0";
    else
        return ans;
}
string stringadd(string a,string b)
{
    if(a.length()>b.length())
        swap(a,b);
    string ans="";
    int len1=a.length();
    int len2=b.length();
    reverse(a.begin(),a.end());
    reverse(b.begin(),b.end());
    int i,j,k,sum=0,carry=0;
    for(i=0;i<len1;i++)
    {

        sum=((a[i]-'0')+(b[i]-'0'))+carry;
        ans.push_back((sum%10)+'0');
        carry=sum/10;
    }
     for(i=len1;i<len2;i++)
    {

        sum=((b[i]-'0'))+carry;
        ans.push_back((sum%10)+'0');
        carry=sum/10;
    }
    if(carry)
        ans.push_back(carry+'0');
    reverse(ans.begin(),ans.end());
    return ans;
}
int main()
{
    string s,div,add;
    long long int n,f,i,j,k=0;
    while(scanf("%lld %lld",&n,&f)==2)
    {
        if(n==0||f==0)
            break;
        if(k>0)
            cout<<endl;
        k++;
        add="",div="";
        for(i=1;i<=n;i++)
        {
            cin>>s;
            add=stringadd(add,s);
        }
        div=stringdiv(add,f);
        cout<<"Bill #"<<k<<" costs "<<add<<": "<<"each friend should pay "<<div<<endl;
    }
    cout<<endl;
    return 0;
}