#include <iostream>

 #include <functional>

 #include <algorithm>

 #include <math.h>

 using namespace std;

 typedef int Heap, Position;

 static Heap Stripes[];

 static int Heap_size = ;

 void Insert(const int, Position);

 int Delete_Max(void);

 void Insert(const int item, Position pos)

 {

     Position s, pr;

     for (s = pos; s > ; s = pr)//大元素上滤

     {

         pr = s %  ==  ? s >>  : (s - ) >> ;

         if (Stripes[pr] < item)

             Stripes[s] = Stripes[pr];

         else break;

     }

     Stripes[s] = item;

 }

 int Delete_Max(void)

 {

     int max = Stripes[], tmp = Stripes[Heap_size--];

     Position pr = , s1, s2, s;

     for (; pr <= Heap_size;)

     {

         s1 = pr << ; s2 = s1 + ;

         if (s2 <= Heap_size)

         {

             s = Stripes[s1] > Stripes[s2] ? s1 : s2;

             Stripes[pr] = Stripes[s];

             pr = s;

         }

         else

         {

             if (s1 <= Heap_size)

             {

                 Stripes[pr] = Stripes[s1];

                 pr = s1;

             }

             break;

         }

     }

     Insert(tmp, pr);

     return max;

 }

 int main(void)

 {

     int n,tmp;

     double ans = ;

     while (~scanf("%d", &n))

     {

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

         {

             scanf("%d", &tmp);

             Insert(tmp, ++Heap_size);

         }

         ans = (double)Delete_Max();//处理初始情况

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

             ans =  * sqrt(ans*(double)Delete_Max());

         printf("%.3f", ans);

     }

     return ;

 }