1. Write a regular expression to match SSNs as per the following rules:

1. Assume SSNs do not start with a 0

2. SSNs can start or end a line or, both

3. SSNs can be followed or preceded by a whitespace

4. SSNs can be followed or preceded by the punctuation symbol set: { , . ; : ? ! }

5. Also, match SSNs of the form xx-xxx-9999 OR XX-XXX-9999, where only the last 4 digits are exposed. For simplicity, assume a string xX-XXXx-9999 will also match
6. The symbol in the SSNs is optional.