package yukicoder275;
import java.util.Arrays;
import java.util.Scanner;
public class Main {
	public static void main(String[] args){
		Scanner sc=new Scanner(System.in);
		int n=sc.nextInt();
		double[] a=new double[n+1];
		a[0]=-99999999;
		
		for(int i=1;i<=n;i++){
			a[i]=sc.nextDouble();
		}
		Arrays.sort(a);
		if(n%2==0){
			System.out.println((a[n/2]+a[n/2+1])/2);
		}else if(n%2==1){
			System.out.println(a[n/2+1]);
		}
		sc.close();
	}
}