In this task, you are given an input list A comprising of numbers and alphabets. You need to extract and sort the unique alphabets in the list. The alphabets in the input list will only be in lowercase. Return -1 if there is no alphabet in the input list.

Ex Input:
['w', 'a', 'm', 'd', '409', 'm', 'v', 's', '7801', 'l', '8551', 'k', '867', 'n', '7731', 'z', '3773', '9137', 'v', 's', 'p', 'p', 'f', 'z', 'g', 'q', 'g', '877', '697', '2057', '8389', '2399', '5263', '2761', '9841', '1781', 'l', '8023']

Ex Output:
a, d, f, g, k, l, m, n, p, q, s, v, w, z


Ex Input:
['4749', '4607', '625', '6907', 't', 'b', '8479', '6505', 'r']

Ex Output:
b, r, t


Ex Input:
['6603', 's', '4285', 'b', 'q', '4737', 'a', '2393', '5609', '6497', 'o', 's', '2283', 'k', '8537', 'p', '9755', '9023', '1157', '3451', 'u', 'v', 'e', 'f', '6245']

Ex Output:

a, b, e, f, k, o, p, q, s, u, v