#include<bits/stdc++.h>
using namespace std;
int main()
{
    int n,i,j=0;
    cin>>n;
    int m[100];
    for(i=0;i<n;i++){
        cin>>m[i];
    } 
    for(i=1;i<=n-1;i++){
        for(j=1;j<=n-i;j++){
            if(m[j-1]<m[j]){
                swap(m[j-1],m[j]);
            }
        }
    }
    printf("%.1f",1.0*(m[0]+m[1]+m[2]+m[3]+m[4])/5);
}
/**************************************************************
	Problem: 1221
	User: wngjinming
	Language: C++
	Result: Accepted
	Time:10 ms
	Memory:2072 kb
****************************************************************/