import java.util.*;

public class Main {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    int N = sc.nextInt();
    int[] num = new int[N];
    for(int i = 0; i < N; i++) {
      num[i] = sc.nextInt();
    }
    Arrays.sort(num);
    double ans = 0;
    if(N % 2 == 0) {
      ans = (double)(num[N / 2] + num[N / 2 - 1]) / (double)2;
    } else {
      ans = num[N / 2];
    }
    System.out.println(ans);
  }
}