#include <cstdio>

 #include <iostream>

 #include <queue>

 #include <algorithm>

 #include <fstream>

 #include <cmath>

 using namespace std;

 const int MAXN = 1e2+;

 int Data[MAXN];

 int main()

 {

     //freopen("input.txt", "r", stdin);

     int N;

     while(scanf("%d", &N)!=EOF)

     {

         for(int i = ; i < N; i++)

             scanf("%d", &Data[i]);

         sort(Data, Data+N, greater<int>() );

         double ans;

         ans = Data[];

         for(int i = ; i < N; i++)

         {

             ans = 2.0*sqrt(ans*Data[i]);

         }

         printf("%.03f\n", ans);

     }

     return ;

 }