Problem Statement 
 You are given a int[] elements. If the arithmetic mean of a nonempty subset of elements is between L and H, inclusive, the subset is considered "good". A subset of a int[] is obtained by removing 0 or more elements from the int[]. Return the number of "good" subsets. 

Definition 
 Class:  ArithmeticalMean  Method:  howMany  Parameters:  int[], int, int  Returns:  long  Method signature:  long howMany(int[] elements, int L, int H)  (be sure your method is public) 




Constraints 
  elements will contain between 1 and 36 elements, inclusive. 
  Each element of elements will be between 25000000 and 25000000, inclusive. 
  Each element of elements will be distinct. 
  L and H will each be between 25000000 and 25000000, inclusive. 
  L will not be greater than H. 

Examples 
0)  
  Returns: 4  All possible arithmetic means are: 1, 2, 3, 14/3, 11/2, 13/2, 10.
Four of them (2, 3, 14/2, 11/2) make "good" subsets. 


1)  
  Returns: 1  There is just one subset and it's "good". 


2)  
  Returns: 0  Same one subset but it's not "good". 


3)  
 