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

class No_275{
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int[] ary = new int[n];
		double median;
		
		for(int i = 0;i <  n;i++){
		ary[i] = sc.nextInt();
		}
		
		Arrays.sort(ary);
		
		if(n % 2 == 0){
			median =(ary[n / 2] + ary[n / 2 - 1]) / 2.0;
		}else{
		median = ary[n / 2];
		}
		
		System.out.println(median);
		}
		}