Problem Statement 
 There are N students standing in a single row, one next to the other, numbered 0 to N1 from left to right. Your goal is to minimize the number of adjacent pairs where one student is a boy and the other is a girl. More precisely, you want to minimize the number of values i, 0 <= i < N1, where student i and student i+1 are of different genders.
You are given the current arrangement as a String row, where the ith character is 'G' if student i is a girl, and 'B' if student i is a boy. In a single move, you can choose two adjacent students and swap their positions. Return the minimum number of moves required to achieve your goal. 

Definition 
 Class:  GirlsAndBoys  Method:  sortThem  Parameters:  String  Returns:  int  Method signature:  int sortThem(String row)  (be sure your method is public) 




Constraints 
  row will contain between 1 and 50 characters, inclusive. 
  Each character in row will be 'G' or 'B'. 

Examples 
0)  
  Returns: 2  You can swap the rightmost girl with the two boys (one after the other) to get "GGGBB", with a minimum of only 1 pair of adjacent students of different gender. 


1)  
  Returns: 0  There is already a single pair of adjacent students of different gender, and there is no arrangement without such pairs at all, so the best solution is to swap nothing. 


2)  
 
3)  
  Returns: 0  With only one student, there is not much swapping to do. 

