#define _GLIBCXX_DEBUG
#define ll long long
#include <bits/stdc++.h>
using namespace std;
using Graph = vector<vector<int>>;

void print(auto a){
  cout << a;
}

void printL(auto a){
  cout << a << endl;
}

void fix(int n){
  cout << fixed << setprecision(n);
}

void AVE(int n, vector<int> A){
  int a = (int)A.size();
  if(n%2 == 0){
    double ans = (double)(A[a/2-1]+A[a/2])/2;
    fix(5);
    printL(ans);
  }else{
    printL(A[a/2]);
  }
}

int main(){
  int N; cin >> N;
  vector<int> A(N);
  for(int i = 0; i < N; i++) cin >> A[i];
  sort(A.begin(), A.end());
  AVE(N, A);
}