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

public class Answer {
	public static void main(String str[]) {
        Scanner sc = new Scanner(System.in);

        int num = Integer.valueOf(sc.nextLine());

        int[] input = new int[num];
        for(int i=0; i<num; i++) {
        	input[i] = Integer.valueOf(sc.next());
        }

        Arrays.sort(input);

        if(num % 2 == 1) {
        	System.out.println(input[num/2]);
        } else {
        	double retval = (double) (input[num/2] + input[num/2-1]) / 2;
        	System.out.println(retval);
        }

	}
}