#include<bits/stdc++.h>
using namespace std;
int a[155],n,i,j;
float q;
int main(){
	cin>>n;
	for(i=0;i<n;i++){
		cin>>a[i];
	}
	for(i=n-1;i>0;i--){
		for(j=0;j<i;j++){
			if(a[j]>a[j+1]){
				swap(a[j],a[j+1]);
			}
		}
	}
	if(n%2==1){
		printf("%.1f",a[n/2]*1.0);
	}else{
		printf("%.1f",(a[n/2-1]+a[n/2])*1.0/2);
	}
	return 0;
}
/**************************************************************
	Problem: 1233
	User: zhangziang
	Language: C++
	Result: Accepted
	Time:6 ms
	Memory:2072 kb
****************************************************************/