import java.util.*;

public class Main {

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