#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
int main()
{
  int n;
  cin >> n;
  vector<int> v;
  for(int i = 0; i < n; i++)
  {
    int j;
    cin >> j;
    v.push_back(j);
  }
  
  sort(v.begin(), v.end());
  float mid;
  if(n % 1 == 0)
  {
    mid = (float)v[n/2];
  }
  else
  {
    mid = ((float)v[n/2] + v[n/2 +-1])/2;
  }
  cout << mid;
}