Distinct Letters

CodePlex - Pramana 2018 Problem description. The word “uncopyrightable” has the interesting property that each of the fifteen letters it contains is only used once. In the English language, there is no word longer that uses distinct letters (each letter used in the word is used once, and once only). There is one other 15 letter word with this property: “dermatoglyphics” (from ancient Greek derma