# Given 2 strings, a and b, return the number of the positions # where they contain the same length 2 substring. # So "xxcaazz" and "xxbaaz" yields 3, since the "xx", "aa", and "az" # substrings ...

# Given a string, return a new string where "not " has been added to the front. # However, if the string already begins with "not", return the string unchanged.