1.6.3.cpp

#include <iostream>
#include <cstdio>
using namespace std;

int main()
{
	int students;
    long payed[1005], average, owedA, owedB;
    double x;
    bool is_first = true;

	for (cin >> students; students; cin >> students)
	{
		if (is_first)
			is_first = false;
		else
			printf("\n");

		average = owedA = owedB = 0;
		for (int i = 0; i < students; ++i)
		{
        	cin >> x;
            payed[i] = int (x *= 100.0);
            average += payed[i];
		}
		average /= students;
		for (int i = 0; i < students; ++i)
			if (payed[i] < average)
				owedA += average - payed[i];
			else
				owedB += payed[i] - average;
		long minOwed = ((owedA <= owedB) ? owedA : owedB);
		printf ("$%.2lf", (minOwed / 100.0));
	}

	return 0;
}