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