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

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