Create a program that returns the number of double letters in a word using recursion.

For example, the word aaron has two double letters and returns 1. The word carrr returns 2 because there are two pairs including the overlapping pair. These are some of the test cases that your method should pass:

0

aa 1

ab 0

aaa 2

aabb 2

aaabb 3

aaaabbb 5

Please turn in the file Recursion.java which contains the method doubleCounter(String input).