In cryptanalysis, words patterns can be a useful tool in cracking simple ciphers.
A word pattern is a description of the patterns of letters occurring in a word, where each letter is given an integer code in order of appearance. So the first letter is given the code 0, and second is then assigned 1 if it is different to the first letter or 0 otherwise, and so on.
As an example, the word "hello" would become "0.1.2.2.3". For this task case-sensitivity is ignored, so "hello", "helLo" and "heLlo" will all return the same word pattern.
Your task is to return the word pattern for a given word. All words provided will be non-empty strings of alphabetic characters only, i.e. matching the regex "[a-zA-Z]+".