Problem 4

You are given a String number of length N containing the digits of a phone number. Each character in number will be a digit ('0'-'9'). To help you memorize the number, you want to divide it into groups of contiguous digits. Each group must contain exactly 2 or 3 digits. There are three kinds of groups: Excellent: A group that contains only the same digits. For example, 000 or 77. Good: A grou