Print every two letters pairs

Created on Dec. 24, 2016 by Julien Palard

Provide a script printing every possible pairs of two letters, only lower case, one by line, ordered alphabetically.

So your output should look like:

1
2
3
4
5
6
7
8

$ python3 solution.py
aa
ab
...
ba
bb
...
zz

Don't write down manually the whole alphabet, use string.ascii_lowercase.