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: Jlwflut, niwfot
Example Output: f, j, l, t, u, w

Example Input: hmdbbuYTWQaDBHW, pGGcTApobbuYTWQapPZDVp
Example Output: a, b, c, d, g, o, p, q, t, u, v, w, y, z

Example Input: AsRnCumQkHKFp, NnBgsAPRnCumQkHtMnVbtX
Example Output:
a, b, c, g, h, k, m, n, p, q, r, s, t, u, v, x