#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

int main(){
  // input
  int N;
  cin >> N;
  vector<int> A(N+1);
  A.at(0)=0;
  for(int i=1;i<=N;i++){
    cin >> A.at(i);
  }
  sort(A.begin(),A.end());
  float ans;
  if(N % 2 == 1){
    int center = (N+1)/2;
    ans = A.at(center);
  } else {
    int center = N/2;
    ans = (A.at(center) + A.at(center+1))/2.0;
  
  }



  cout << ans << endl;
  // output 
}