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:
['477', '3931', 'g', '5967', 'm', '9845', '1607', 'a', '1749', 'k', 'j', '7945', '9125', 'v', 'n', 's', '5185', '1117', '17', 'x', '4149']

Ex Output:
a, g, j, k, m, n, s, v, x


Ex Input:
['h', 'b', '9601', 'h', 'h', 'h', '8099', '8265', 'i', 'd', '8791', 'p', '8059', '4309', '501', '2581', '9837', '157', '4785', '5925', 'q', '8491', '4779', 'r', 'l', 'k', '3679', 'v', 'g', 'g', '9731', '1909', '9783', 'f', '4293', '5009', 'o', '3057', '3157', 'c', '5587', 'b', 'f', 'd', 'k']

Ex Output:
b, c, d, f, g, h, i, k, l, o, p, q, r, v


Ex Input:
['5903', 'b', '207', '7071', '1325', 'q', 'x', 's', '1673', 's', '4665', '5865', 'a', '6085', '3075', '5079', 'x', '2319', 'm', 'm', 'b']

Ex Output:

a, b, m, q, s, x