Problem Statement 
 Given an inclusive range of numbers you will first sort them in ascending order by their digit sum
(sum of their decimal digits). Ties are settled by the numbers' values, lower numbers first. You
will then return the value at location pos (0based) in the newly sorted list. For example:
rangeLow = 0
rangeHigh = 10
pos = 3
The sorted range is : 0,1,10,2,3,4,5,6,7,8,9. The value at position 3 is 2.
Note that 10 comes before 2 since the digit sum of 10 is 1 whereas the digit
sum of 2 is 2. Also note that 10 comes after 1 even though they have the same
digit sum since 10 is greater than 1. 

Definition 
 Class:  SumSort  Method:  valueAt  Parameters:  int, int, int  Returns:  int  Method signature:  int valueAt(int rangeLow, int rangeHigh, int pos)  (be sure your method is public) 




Constraints 
  rangeLow will be between 0 and 1000000000 (10^9) inclusive 
  rangeHigh will be between 0 and 1000000000 (10^9) inclusive 
  rangeLow will be less than or equal to rangeHigh 
  pos will be between 0 and (rangeHigh  rangeLow) inclusive 

Examples 
0)  
  Returns: 2  This is the example above 


1)  
  Returns: 79  The numbers are sorted as:
80, 81, 90, 82, 91, 83, 92, 84, 93, 85, 86, 78, 87, 79, 88, 89 


2)  
 