#include <bits/stdc++.h>
using namespace std;
int main(){
	float s;
	int i,n,j;
	cin>>n;
	int a[n];
	for(i=1;i<=n;i++){
		cin>>a[i-1];
         }
	for(i=1;i<=n-1;i++){
		for(j=1;j<=n-i;j++){
			if(a[j-1]>a[j])
			swap(a[j-1],a[j]);
	    }
	}
	
	s=(a[n-1]+a[n-2]+a[n-3]+a[n-4]+a[n-5])/5.0;
	printf("%.1f",s);
	
	
	return 0;
	}
/**************************************************************
	Problem: 1221
	User: fzy001
	Language: C++
	Result: Accepted
	Time:9 ms
	Memory:2072 kb
****************************************************************/