How many vocabulary words were used in Green Eggs and Ham?

'Green eggs and Ham' contains 50 different words. 49 of the words are only one syllable in length; the only word longer than one syllable is "anywhere" (excluding the hyphenated 'Sam-I-Am'). Supposedly, Dr Seuss' publisher challenged him to write a book using no more than 50 words and 'Green Eggs and Ham' was the result.