#include <stdio.h>
 
int main() {
	int n, i;
	double average, negDiff, posDiff, minDiff, total;
 
	while (scanf("%d", &n) == 1) {
		if (n == 0) break;
		double money[n];
		total = 0.0;
		for (i = 0; i < n; i++) {
			scanf("%lf", &money[i]);
			total += money[i];
		}
		average = (long) ((total / n) * 100.0) / 100.0;
		negDiff = posDiff = 0.0;
		for (i = 0; i < n; i++) {
			if (money[i] > average)
				posDiff += (long) ((money[i] - average) * 100.0) / 100.0;
			else
				negDiff += (long) ((average - money[i]) * 100.0) / 100.0;
		}
		minDiff = posDiff > negDiff ? negDiff : posDiff;
		printf("$%.2lf\n", minDiff);
	}
	return 0;
}

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MwoxMC4wMCAyMC4wMCAzMC4wMAo0CjE1LjAwIDE1LjAxIDMuMDAgMy4wMQo0Cjk5OTkuMSA5OTk5LjEgOTk5OS4wIDk5OTkuMQow

3
10.00 20.00 30.00
4
15.00 15.01 3.00 3.01
4
9999.1 9999.1 9999.0 9999.1
0