#include<bits/stdc++.h>
using namespace std;
int main(){
	int n,a[105]={0},i,j;
	float h;
	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]);
            }
        }
    }
	h=(a[0]+a[1]+a[2]+a[3]+a[4])/5.0;
    printf("%.1f",h);
	return 0;
}
/**************************************************************
	Problem: 1221
	User: lijinkai
	Language: C++
	Result: Accepted
	Time:7 ms
	Memory:2072 kb
****************************************************************/