For this problem you want to reduce each word to a "pattern" such that morphgrams have the same pattern.

To do this, make the first unique letter in the word be mapped to the next letter in the alphabet; so FOOD becomes ABBC. Now you must check if patterns match. The naive way to do this is to check every pair of words.

To optimize this, use a map. For each pattern, count the number of occurrences. Let ~x~ be the number of occurrences of a given pattern. Then there are:

$$\displaystyle {x \choose 2} = \frac{x \times (x - 1)}{2} $$

pairs that match for this given pattern. Finally, add up all your totals for the final answer.