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:
['u', 'o', 'b', 'b', '5873', 'w', 'v', '4171', '7957', '3501', '2563', 'l', 'q']

Ex Output:
b, l, o, q, u, v, w


Ex Input:
['p', '4329', '2437', '6279', 'u', '459', 'f', 'c', 'i', 'w', 'n', 't', '429', 'n', '73', '4995', 'p', 'z', '8459', '6133', 'y', 'r', '4057', 'a', '2717', '7803', 'r', 'm', '2879', '6989', '7223', 'v', '7929']

Ex Output:
a, c, f, i, m, n, p, r, t, u, v, w, y, z


Ex Input:
['o', 'c', '3363', '2427', '4789', '3901', 'u', '3149', 'b', 'n', '7431', '3165', 'c', '5511', '9195', '4629', '117', '5711', 'm', '677', '5135', '8061', 'r', 'l', 'x', 'w', 'a', 'k', 't', 'u', 'l', 'c', '1531']

Ex Output:

a, b, c, k, l, m, n, o, r, t, u, w, x