In this task, you are given two strings A,B. Find the longer of the two lists, convert it to lowercase, and return all the unique alphabets used in it. The two input strings are never equal.

Example Input: gbSfpXc, lSSfnu
Example Output: b, c, f, g, p, s, x

Example Input: oupmIZoowUjzrWccNhstElTcjRqCCjQhmTz, MiDrWOXzpIyWccNhstElTcjRqiwvUmJkiD
Example Output: c, e, h, i, j, l, m, n, o, p, q, r, s, t, u, w, z

Example Input: nWgKceFtEyBbNVaffdDZmUwyK, PMkMRjLAyBbNVaffdDEevvhK
Example Output:
a, b, c, d, e, f, g, k, m, n, t, u, v, w, y, z