import java.util.*;

public class Main {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    int N = sc.nextInt();
    ArrayList<Integer> num = new ArrayList<Integer>();
    for(int i = 0; i < N; i++) {
      int a = sc.nextInt();
      if(!(num.contains(a))) { 
        num.add(a);
      }
    }
    Collections.sort(num);
    double ans = 0;
    int si = num.size();
    if(si % 2 == 0) {
      ans = (double)(num.get(si / 2) + num.get(si / 2 - 1)) / (double)2;
    } else {
      ans = num.get(si / 2);
    }
    System.out.println(ans);
  }
}