Input string: Output string: i bought twenty-one books from professor smith
Input string: Output string: doctor
Input string: Output string: for example world war the second and other things
Input string: Output string: ninety-nine helium-oxygen balloons
Input string: Output string: four four four
Input string: Output string: nothing to normalize
Input string: Output string: thirteen
Input string: Output string: this one hundred and seven plus thirty-four times three minus four
Input string: Output string: aaa and bbb
Input string: Output string: a slash slash b plus c hyphen d star
Input string: Output string: fifty six thousand five hundred and sixty
Input string: Output string: one hundred twenty-three million four hundred fifty-six hundred seven hundred eighty nine
Input string: Output string: four eight five five five four three oh three one two
Input string: