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

public class No275 {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();

        double[] a = new double[n];
        for (int i = 0; i < n; i++) {
            a[i] = sc.nextInt();
        }
        Arrays.sort(a);

        double result = 0;

        if (n % 2 != 0) {
            result = a[n / 2];
        } else {
            result = (a[n / 2 - 1] + a[n / 2]) / 2;
        }

        System.out.println(String.format("%#.1f", result));

        sc.close();
    }

}