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

int main() {
  // 入力
  int N;
  cin >> N;
  int a[N];
  for (int i = 0; i < N; i++) cin >> a[i];

  sort(a, a + N);
  if (N & 1) {
    cout << a[N/2] << endl;
  } else {
    cout << (a[N/2-1] + a[N/2]) / 2.0 << endl;
  }

  return 0;
}