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

/* Perform bubble sort in ascending order. */
void bubble_sort(int n, double *a)
{
  int i, j;

  for (i = 0; i < n - 1; ++i) {
    for (j = 0; j < n - 1 - i; ++j) {
      if (a[j] > a[j + 1]) {
        double tmp = a[j];
        a[j] = a[j + 1];
        a[j * n] = tmp; /* Should be a[j + 1] = tmp; */
      }
    }
  }
}

int main(void) {
  int n;
  double *a;
  int i;
  
  scanf("%d", &n);
  a = malloc(sizeof(double) * n);
  for (i = 0; i < n; ++i) {
    scanf("%lf", &a[i]);
  }
  
  bubble_sort(n, a);  

  printf("%f\n", a[n / 2]);
  
  free(a);
  return 0;
}