import java.util.Arrays;
import java.util.Scanner;
 
class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int[] a = new int[n];
		for(int i=0;i<n;i++){
			a[i] = sc.nextInt();
		}
		double median;
		Arrays.sort(a);
		if(n%2==0){
			median = (a[n/2-1]+a[n/2])/2.0;
		} else {
			median = a[n/2];
		}
		System.out.printf("%.1f\n", median);
	}
}