package yukicoder;

import java.util.Arrays;
import java.util.Scanner;

public class yuki275 {
	
	public static void main(String[] args) {
	
		Scanner scan = new Scanner(System.in);
		int count = scan.nextInt();
		int num[] = new int[count];
		
		for (int i = 0; i < count; i++ ) {
			num[i] = scan.nextInt();
		}
		scan.close();
		Arrays.sort(num);
		
		if (count % 2 == 0) {
			count /= 2;
			double  ans = ((double)num[count - 1] + (double)num[ count ])/2;
			System.out.println(ans);
		} else {
			System.out.println( num[count/2]);	
		}
	}
}