package yukicorder;
import java.util.Scanner;

public class QNo275 {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		short n = sc.nextShort();
		short[] a = new short[n];
		short[] out = new short[n];
		for(int i=0;i<n;i++){
			a[i] = sc.nextShort();
		}
		for(short i =n;i>0;i--){
			partHeap((short)(i-1),a);
		}
		for(short k=n;k>1;k--){
			out[k-1] = a[0];
			a[0] = a[k-1];
			a[k-1] = -10000;
			partHeap((short)0,a);
		}
		
	    double center = -10000;
	    if(n%2==0) center = (out[n/2-1] + out[n/2])/2;
	    else center = out[n/2];
	    System.out.println(center);
		
	}
	
	private static void partHeap(short parent,short[] a){
		short cand = -10000;
		short lr = -1;
		short pare = -10000;
		try{
			pare = a[parent];
			cand = a[parent*2];
			lr = 0;
			if(cand<a[parent*2+1]){
				cand = a[parent*2+1];
				lr = 1;
			}	
		}catch(IndexOutOfBoundsException e){
			if(lr==-1) return;
		}
		if(cand > pare){
			a[parent] = cand;
			a[parent*2+lr] = pare;
			partHeap((short)(parent*2+lr),a);
		}
	}
}