#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>

int main()
{
	int num = 0;
	int nums[1000] = { 0 };
	int a = 0;
	int b = 0;
	float ans = 0;
	scanf("%d", &num);

	for (int i = 0;i < num;i++)
	{
		scanf("%d", &nums[i]);
	}

	for (int i = 0;i < num;i++)
	{
		for (int j = i + 1;j < num;j++)
		{
			if (nums[j] < nums[i])
			{
				int tmp = nums[i];
				nums[i] = nums[j];
				nums[j] = tmp;
			}
		}
	}

	if (num % 2 == 0)
	{
		int c = 0;
		int index = (num / 2) - 1;
		if (index < 0)
		{
			index = 0;
		}
		a = nums[num / 2];
		b = nums[index];

		c = a + b;
		ans = c / 2;
	}
	else
	{
		ans = nums[num / 2];
	}
	
	printf("%.6f\n", ans);

	return 0;
}