word chain challenge
Given a wordlist (say, the English dictionary), if you can remove a letter from a word and the new word is a known word (in the wordlist), this makes a chain of length 2. If you can repeat this for a second time, you continue to the third level, and so on.
For example, the word "trees" has a chain length of 3:
Using the system dictionary (code snippet provided), how long is the longest chain? And which words make the longest chain?
from words import WORDS