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: KztAcEdKEVjbjhitKQr, qGMLTEdKEVjbjzxkT
Example Output: a, b, c, d, e, h, i, j, k, q, r, t, v, z

Example Input: DOvnfRVZgJFrzHo, GaApmOnfRVZgJoDN
Example Output: a, d, f, g, j, m, n, o, p, r, v, z

Example Input: wtPLjvaeRavZRUJzpWKrDUPq, lRjFzOjTyqRavZRUJzpWXsJhTgy
Example Output:
a, f, g, h, j, l, o, p, q, r, s, t, u, v, w, x, y, z