#include<bits/stdc++.h>
using namespace std;
int main(){
	int n,i,l;
	float x;
	cin>>n;
	int a[n];
	for(i=0;i<n;i++){
		cin>>a[i];
	} 
	for(l=n-1;l>=1;l--){
		for(i=0;i<l;i++){
			if(a[i]>a[i+1]){
				swap(a[i],a[i+1]);
			}
		}
	}
	if(n%2==0){
		x=(a[n/2-1]+a[n/2])/2.0;
	}else{
		x=a[n/2];
	}
	printf("%.1f",x);
	return 0;
}

/**************************************************************
	Problem: 1233
	User: tangkaixuan
	Language: C++
	Result: Accepted
	Time:9 ms
	Memory:2072 kb
****************************************************************/