Java scan input word, then generate random number based on length, excluding first and last characters

I'm looking to create a program where the user enters a word, then the program generates a random number that corresponds to a character in the word, not including the first or last letter of the word.

Ex: Entered word: Computer

generate random number between 1-6

Entered word: Phone

generate random number between 1-3

I'm not sure how to get it to exclude the first and last positions of the entered word. Any help would be greatly appreciated.