Types: S: str, a_i: str, v_i: int
Ranges: 2 ≤ N ≤ 26, v_i ≤ 26, a_i in {'a', 'b', ..., 'z'}
Addtl Info: S satisfies the BNF <winner> ::= <person> | "[" <winner> "-" <winner> "]" and contains each a_i exactly once and no other lowercase letters.