#include <bits/stdc++.h>

using namespace std;

#define int long long

struct f{
	int yummy;
	bool eaten = false;
};

f fruit[100000];

int ans = 0;
int n;

void dfs(int day,int num){
	if(day == n){
		ans = max(ans,num);
		return;
	}else{
		for(int i = 0;i < n;++i){
			if(fruit[i].eaten == false){
				int get = fruit[i].yummy;
				for(int j = 0;j < day;++j){
					get = sqrt(get);
				}
				fruit[i].eaten = true;
				dfs(day+1,num+get);
				fruit[i].eaten = false;
			}
		}
	}
}

signed main(){
	cin>>n;
	for(int i = 0;i < n;++i){
		cin>>fruit[i].yummy;
	}
	dfs(0,0);
	cout<<ans;
}