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: qjIYietWV, aFIYiheM
Example Output: e, i, j, q, t, v, w, y

Example Input: hRUdeiasqtueQRAFzR, vsJveiasqtueQRAFLWqPyU
Example Output: a, e, f, i, j, l, p, q, r, s, t, u, v, w, y

Example Input: GSMvShghiJZVTRA, WYochghiJrVNs
Example Output:
a, g, h, i, j, m, r, s, t, v, z