#include <iostream>
#include <iomanip>

using namespace std;

int main(){
	int a[100],i,j,t,n ;
	double v;
	cin>>n;
	for(i = 0;i < n;i++){
		cin>>a[i];
	}
	
	
	for(i = 1;i < n;i++){
		for(j = 0;j < n - i;j++){
			if(a[j] > a[j + 1]){
				t = a[j];
				a[j] = a[j + 1];
				a[j + 1] = t;
			}
		} 
	}
	
	if(n % 2 == 0){
		v = (a[n / 2] + a[n / 2 - 1]) * 1.0 / 2;
	}else{
		v = a[n / 2];
	}
	
	cout<<fixed<<setprecision(1)<<v<<endl;
	

}
/**************************************************************
	Problem: 1233
	User: admin
	Language: C++
	Result: Accepted
	Time:8 ms
	Memory:2072 kb
****************************************************************/