A good first input in general probably looks like a bad password, like 123abcXYZ! with a little bit of every type of character (lower, upper, num, symbols)
(The NIST SP 800-63 Standard Password "Fall2026!" also works, but it's less efficient, and changes every quarter!)
Hehe, I really like them. And I always recommend those. It's not always that you have some nice books on deep concepts in mathematics for the "general" public