Types: n: int, s: str
Ranges: 1 ≤ n ≤ 10,000, s consists of {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'u'}, s ends with 'u'
Addtl Info: Input consists of at most 50 datasets, each terminated by a line with a zero.