#include<bits/stdc++.h>
using namespace std;
int n , a[100005] ;
long long sum ;
double maxx ;
bool cmp(int x , int y){
  return x > y ;
}
int main()
{
  cin >> n ;
  for ( int i = 1 ; i <= n ; i ++ )
  {
  	cin >> a[i] ;
  }
  sort ( a + 1 , a + 1 + n , cmp ) ;
  for ( int i = 1 ; i <= n ; i ++ )
  {
  	sum += a[i] ;
  	maxx =  max  ( maxx , sum * 1.0 / i * sum ) ;
  }
  printf ( "%.100lf" , maxx ) ;
  return 0; 
}