#include <stdio.h>

int main()
{
	int n;
	int alley[1000];
	int i, j, k;
	int temp;
	double ans;

	scanf("%d", &n);
	for (i = 0; i < n; i++) {
		scanf("%d", &alley[i]);
	}

	for (j = 0; j < n - 1; j++) {
		for (k = 0; k < n - j - 1; k++) {
			if (alley[k] > alley[k + 1]) {
				temp=alley[k];
				alley[k] = alley[k + 1];
				alley[k + 1] = temp;
			}
		}
	}
	if (n % 2 == 0) {
		ans = ((alley[n / 2 - 1] + alley[n / 2]) / 2.0);
	}
	else {
		ans = (double)alley[n / 2];
	}
	printf("%.1f", ans);
	return 0;
}