import java.io.*;
import java.util.*;

class Main275 {
	
	public static void out (Object out) {
		System.out.println(out);
	}
	
	public static void main (String[] args) throws IOException {
		BufferedReader br = 
			new BufferedReader(new InputStreamReader(System.in));
		
		int n = Integer.parseInt(br.readLine());
		int[] nums = new int[n];
		String[] str = br.readLine().split(" ");
		
		for (int i = 0; i < n; i++)
			nums[i] = Integer.parseInt(str[i]);
		
		Arrays.sort(nums);
		
		if (n % 2 == 0)
			out((nums[n / 2] + nums[n / 2 - 1]) / 2.0);
		else
			out(nums[n / 2]);
		
	}
}