#include <bits/stdc++.h>
using namespace std;

int main(){
  int N;
  cin >> N;
  vector<double> a(N);
  
  for(int i = 0; i < N; i++){
      cin >> a.at(i);
  }
  sort(a.begin(), a.end());

  if(N%2 == 0){
      cout << (a.at(N/2) + a.at(N/2 - 1))/2;
  }else{
      cout << a.at(N/2);
  }
}