Write a regular expression that matches fractions. A fraction consists of one or more digits followed by a / followed by one or more digits. It may consist of an optional + or - character before the first digit in the numerator. The denominator must be non-zero and positive.

Note This is a regex only challenge. You are not required to write code. Do not change *anything * in the stub code provided below except for the regular expression, otherwise your submission will be rejected by the checker.