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

Ex Output:
b, r, t


Ex Input:
['l', '1213', 'm', 'k', '7825', '3501', '2397', '2313', 'v', '4119', 'h', 't', '6137', 'l', '9851', 'q', '9661', 'b', 'z', '1437', '1759', 'l', '611', '5085', '4443', 'n', 'u', 'b', '2511', '6023', '7157', 'n', '9921', 'o', 'a', 'o', 'w', 't', 'o', '1607', '6751', 'n', 'b']

Ex Output:
a, b, h, k, l, m, n, o, q, t, u, v, w, z


Ex Input:
['z', 'z', 'n', '569', '8255', '6397', 'a', '1073', '3971', 'o', 'v', '1151', '7697', '1341', '8573', '8119', 'l', '4561', 'v', '2323', '1003', '699', 'l', 's', '3601', 'k', 'g', 'h', 'j', 'a', '3073', 'y', '2075', 'q', 's', '5111', 'e', 'h', '8085', '7057']

Ex Output:

a, e, g, h, j, k, l, n, o, q, s, v, y, z