import java.util.*;

class Main{
	public static void main(String args[]){
		Scanner sc = new Scanner(System.in);
		ArrayList<Integer> array = new ArrayList<Integer>();
		
		int num = Integer.parseInt(sc.next());

		for(int i = 0; i < num; i++){
			array.add(Integer.parseInt(sc.next()));
		}

		Collections.sort(array);

		switch(num % 2){
		case 0:
			System.out.println( (double)(array.get(num / 2) + array.get((num / 2) - 1)) / 2 );
			break;
		case 1:
			System.out.println(array.get(num / 2));
			break;
		}
		
	}
}