#include <stdio.h>

void QuickSort(int *, int, int);

int main(void)
{
  int n, i, input_num[1000], idx;
  float median;
  scanf("%d", &n);
  for(i = 0; i < n; i++){
    scanf("%d", &input_num[i]);
    }
  QuickSort(input_num, 0, n - 1);

  idx = n / 2;
  median = (float)input_num[idx];
  if(n % 2 == 0 && n > 1){
    median += (float)input_num[idx - 1];
    median = median / 2.0;
  }

  printf("%0.1f\n", median);

  return 0;
}

void QuickSort(int *a, int first, int last)
{
	int i, j, x, t;

	x = a[(first + last) / 2];
	i = first; j = last;
	for( ; ; ){
		while(a[i] < x) i++;
		while(x < a[j]) j--;
		if(i >= j) break;
		t = a[i]; a[i] = a[j]; a[j] = t;
		i++; j--;
	}
	if(first < i - 1) QuickSort(a, first, i - 1);
	if(j + 1 < last) QuickSort(a, j + 1,last);
}