In the example, "12." is converted to "twelve." Does this hold true for all punctuation marks? And does it apply to punctuation both before and after a number? For example, should "%8(" become "%eight("? Or does starting with punctuation mean it's not considered a number? Are there always spaces between numbers? It is true in the sample input, but not stated as rule in the conditions. For example, should "2#8" become "two#eight"? Or is this not considered a number (or only the 2 considered a number)? Finally, what are we supposed to do with numbers starting with 0? For example, are we meant to interpret "09" the same as "9"?
clarification on punctuation, spacing rules