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: RLFJPeUYhcBJcbCCuwCpzxShrbaGEsTyzT, qUmrmEYhcBJcbCCuwCpzxYVmPkHFr
Example Output: a, b, c, e, f, g, h, j, l, p, r, s, t, u, w, x, y, z

Example Input: AjFwxWQCKWaRDp, BXOUxWQCKWabWlbxE
Example Output: a, b, c, e, k, l, o, q, u, w, x

Example Input: rIDpzsfgidj, YbzsfgOZMI
Example Output:
d, f, g, i, j, p, r, s, z