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

public class No275 {

	public static void main(String[] args) {
		Scanner scanner = new Scanner(System.in);
		int[] noList = new int[scanner.nextInt()];
		for(int index = 0; index < noList.length; index++) {
			noList[index] = scanner.nextInt();
		}
		Arrays.sort(noList);
		if(noList.length % 2 == 1) {
			System.out.println(noList[noList.length / 2]);
		}
		else {
			System.out.println((noList[(noList.length / 2) - 1] + noList[noList.length / 2]) / 2.0);
		}
		scanner.close();
	}
}