#include<bits/stdc++.h>
using namespace std;
int main(){
  int i,j,n;
  int a[100]={0};
  float s=0;
  cin>>n;
  for(i=0;i<n;i++) cin>>a[i];
  for(i=0;i<n-1;i++)
  	for(j=0;j<n-i-1;j++)
  		if(a[j]>a[j+1]) swap(a[j],a[j+1]);
  for(i=n-5;i<n;i++) s=s+a[i];
  s=s/5;
  printf("%.1f",s);
  return 0;
}
/**************************************************************
	Problem: 1221
	User: wtq001
	Language: C++
	Result: Accepted
	Time:8 ms
	Memory:2072 kb
****************************************************************/