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:
['p', 'g', 'q', 'e', '8045', '9999', '9555', '7995', '7195', 'z', 't', '5223', '3699', 'i', '4797', '3817', 'x', 'y', 'w', 'o', '8915', '7803', 'n', '1117', 'c', '9647', 'p', 'e', '9669', '4845', '9255', '4545', '3693', '6871', 'w', '4327', '3285', 'k', 'f', 'x', 'i', 'b', '5967', '6601']

Ex Output:
b, c, e, f, g, i, k, n, o, p, q, t, w, x, y, z


Ex Input:
['l', '6313', '3199', 'w', '249', '8747', '7391', '3871', '173', 'x', 'o', '8647', '4413', '3645', '6123', '701', 'q', '2147', '4289', '7333', '533']

Ex Output:
l, o, q, w, x


Ex Input:
['4299', '8125', 'z', '6931', '5643', 'z', 'k', '5963', 'x', '9899', '1139', '819', '589', '4479', '5177', '7887', '6465', '2909', 'l', 'q', 'z', '2313', 'u', '2517', '9075', '7441', 'x', 'x', '5489', '6377', 'q', '4671', '7171', 'r', '6879', '9517', 'a', '3259', 'z', 'i', '7941', 'p', '6341', '2031', 'c']

Ex Output:

a, c, i, k, l, p, q, r, u, x, z