**author Rich Wareham (rjw57)**

This is an "holistic" puzzle in that one needs to look at the structure of the graph as a whole to solve the problem.

There are 10 nodes. If one thinks of ten digits and plays around with ways of deriving one digit from another one might eventually end up with ONE → 3, TWO → 3, THREE → 5, SIX → 3, etc, etc.

This is the graph shown and *X*, *Y* and *Z* are the unambiguous nodes "3", "5"
and "4". The answer is therefore "354".