#include<bits/stdc++.h>
using namespace std;
int main(){
	int n,i,j;
	cin>>n;
	int a[n];
	for(i=0;i<n;i++){
		cin>>a[i];
	} 
	for(i=n-1;i>0;i--){
		for(j=0;j<n-1;j++){
			if(a[j]>a[j+1]){
				swap(a[j],a[j+1]);
			}
		}
	}
	if(n%2!=0){
		printf("%.1f",a[n/2+1-1]*1.0);
	}else{
		printf("%.1f",(a[n/2-1]+a[n/2+1-1])/2.0);
	}
}
/**************************************************************
	Problem: 1233
	User: linzihang
	Language: C++
	Result: Accepted
	Time:8 ms
	Memory:2072 kb
****************************************************************/