## Problem Description

A number of students are members of a club that travels annually to exotic
locations. Their destinations in the past have included
Indianapolis, Phoenix, Nashville,
Philadelphia, San Jose, and Atlanta. This spring they are planning a trip
to Eindhoven.

The group agrees in advance to share expenses equally, but it is not
practical to have them share every expense as it occurs. So individuals
in the group pay for particular things, like meals, hotels, taxi rides,
plane tickets, etc. After the trip, each student's expenses are tallied
and money is exchanged so that the net cost to each is the same, to within
one cent. In the past, this money exchange has been tedious and time
consuming. Your job is to compute, from a list of expenses, the minimum
amount of money that must change hands in order to equalize (within a cent)
all the students' costs.

## Input

Standard input will contain the information for several trips. The information
for each trip consists of a line containing a positive integer, n, the
number of students on the trip, followed by n lines of input, each containing
the amount, in dollars and cents, spent by a student. There are no more
than 1000 students and no student spent more than $10,000.00. A single
line containing 0 follows the information for the last trip.

## Output

For each trip, output a line stating the total amount of money, in dollars
and cents, that must be exchanged to equalize the students' costs.

## Sample Input

3
10.00
20.00
30.00
4
15.00
15.01
3.00
3.01
0

## Sample Output

$10.00
$11.99

## Source

Waterloo local 1999.01.31