import java.util.Arrays;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.Scanner;
import java.util.Set;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		
		final int N = sc.nextInt();
		
		int[] arr = new int[N];
		for(int i = 0; i < N; i++){
			arr[i] = sc.nextInt();
		}
		
		Arrays.sort(arr);
		
		if(N % 2 == 0){
			System.out.printf("%.8f\n", (double)(arr[N / 2 - 1] + arr[N / 2]) / 2);
		}else{
			System.out.println(arr[N / 2]);
		}
	}

}