#include <bits/stdc++.h>

using namespace std;

int main(){
  int n;
  cin >> n;
  double nums[n];
  int i,j,index=1;
  for(i = 0; i < n; i++){
    cin >> nums[i];
  }

  double min = nums[0];
  int minIndex;
  for(i = 0; i < n; i++){
    min = nums[i];
    int change = 0;
    for(j = i; j < n; j++){
      if(min > nums[j]){
        min = nums[j];
        minIndex = j;
        change = 1;
      }
    }
    if(change){
      double tmp = nums[i];
      //cout << "swap " << tmp << " and " << nums[minIndex] << endl;
      nums[i] = nums[minIndex];
      nums[minIndex] = tmp;
    }
  }
  double ans;
  if(n % 2 == 0){
    ans = (nums[n/2] + nums[(n/2) - 1]) / 2;
  }else{
    ans = nums[n/2];
  }
  cout << ans << endl;
  return 0;
}