import java.util.Scanner;

public class No275{
	static void swap(int[]a,int idx1,int idx2) {
		int t = a[idx1];	a[idx1]=a[idx2];	a[idx2]=t;
	}
	static void quickSort(int[]a,int left,int right) {
		int pl = left;
		int pr = right;
		int x = a[(pl+pr)/2];

		do {
			while(a[pl]<x) pl++;
			while(a[pr]>x) pr--;
			if(pl <= pr)
				swap(a,pl++,pr--);
		}while(pl<=pr);

		if(left<pr) quickSort(a,left,pr);
		if(pl<right)quickSort(a,pl,right);
	}

	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();
		}

		quickSort(a,0,n-1);

		double med=0.0;

		if(n%2==0) {
			med = (a[(n/2)-1]+a[n/2])/2.0;
		}
		else if(n%2!=0) {
			med = a[n/2];
			}

		System.out.println(med);


	}

}