Input:  Krithi Potak <krithipotak388@gmail.com>
Output: krithipotak388@gmail.com

Input:  "John Doe" <john@example.com>
Output: john@example.com

Input:  user@domain.com
Output: user@domain.com

Input:  Test User <test@test.com>
Output: test@test.com

Input:  simple@email.com
Output: simple@email.com