#include<cstdio>
#include<iostream>
#include<string>
#include<algorithm>
#include<iterator>
using namespace std;
/*
* A solution for "The Trip" problem.
* UVa ID: 10137
*/
#include <stdio.h>
int main (int argc, const char * argv[]) {
/* number of students in the trip */
long numOfStudents;
/* the total sum of money spent */
double total;
/* the total amount of money to exchange in order to equalize */
double exchange;
/* the equalized trip amount to be payed by each student */
double equalizedAmount;
/* difference between the equalized amount and the amount spent */
double diff;
/* sum of all negative differences */
double negativeSum;
/* sum of all positive differences */
double positiveSum;
/* iterator */
int i;
while(scanf("%ld", &numOfStudents) != EOF) {
/* 0, ends the program */
if (!numOfStudents) {
return 0;
}
/* keeps the amount of money spent by each student */
double amountSpent[numOfStudents];
/* clean */
total = 0;
negativeSum = 0;
positiveSum = 0;
for (i = 0; i < numOfStudents; i++) {
scanf("%lf
", &amountSpent[i]);
total += amountSpent[i];
}
equalizedAmount = total / numOfStudents;
for (i = 0; i < numOfStudents; i++) {
/* to ensure 0.01 precision */
diff = (double) (long) ((amountSpent[i] - equalizedAmount) * 100.0) / 100.0;
if (diff < 0) {
negativeSum += diff;
} else {
positiveSum += diff;
}
}
/* when the total amount is even, these sums do not differ. otherwise, they differ in one cent */
exchange = (-negativeSum > positiveSum) ? -negativeSum : positiveSum;
/* output result */
printf("$%.2lf
", exchange);
}
return 0;
}