import java.math.BigDecimal;
import java.util.Arrays;
import java.util.Scanner;

public class Main {

	static Scanner sc = new Scanner(System.in);

	public static void main(String[] args) {

		int n = sc.nextInt();
		int[] as = new int[n];

		for(int i = 0; i < n; i++) {
			as[i] = sc.nextInt();
		}

		Arrays.sort(as);
		if(n % 2 != 0) {
			System.out.println(as[n / 2]);
		} else {
			double a = (as[(n / 2) - 1] + as[n / 2]) / 2.0;
			BigDecimal bd = new BigDecimal(a).setScale(1);
			System.out.println(bd);
		}
    }
}