#include<bits/stdc++.h>
using namespace std;
int main(){
    int n,a[200],v=0;
    float z;
    cin>>n;
    for(int i=1;i<=n;i++){
        cin>>a[i];
    }
    for(int i=1;i<n;i++){
    for(int j=1;j<=n-i;j++){
        if(a[j]<a[j+1])  swap(a[j],a[j+1]);
        }
        
    }
    if(n%2==0){
    	v=a[n/2+1]*1.0;
    }else{
    	v=(a[n/2]+a[n/2+1])*1.0/2;
    }
    printf("%.2f\n",v);

    return 0;
}
/**************************************************************
	Problem: 1233
	User: lidongbo
	Language: C++
	Result: Wrong Answer
****************************************************************/