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

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int a = sc.nextInt();
        int[] bbb = new int[a];
        for(int i = 0;i<a;i++){
        	int b = sc.nextInt();
        	bbb[i] = b;
        }
        Arrays.sort(bbb);
        double median;
        int m = bbb.length / 2;
        if ( 0 != ( bbb.length % 2 ) ) {
        	median = (double)bbb[ m ];
        }
        else {
        	median = (double)( bbb[ m - 1 ] + bbb[ m ] ) / 2.0;
        }
        System.out.println(median);
    }
}