#include<bits/stdc++.h>
using namespace std;
int main(){
    int n,i,a[110]={0},j;
    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]);
            }
        }
    }
    printf("%.1f",(a[0]+a[1]+a[2]+a[3]+a[4])/5.0);
      
}

/**************************************************************
	Problem: 1221
	User: linmiaoling
	Language: C++
	Result: Accepted
	Time:10 ms
	Memory:2072 kb
****************************************************************/