HARDER PROBLEM: skip if you have trouble

Given an input String, find and return the last word in the input. A word always ends in a letter, and after the letter is zero or more periods, followed by one or more spaces unless the word is the end of the String. So "don't" is actually a word for this purpose, but not "teachers'" (apostrophe at the end means it isn't a letter). "blah." is a word ending in the period, for which this method should just return "blah". Precondition: the input will have at least one word.

HINT: use Character.isLetter(str.charAt(index)) to find out the location of the last letter. You probably need to use a loop from the back, unless you are being all fancy.

Super-advanced challenge: what is the minimum number of statements you can use to solve this?