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:
['6627', '8037', 'q', 'e', 'j', 'p', '9613', '9317', 'm', 'm', '5345', 'f', '8105', '5665', '4175', '4793', '3707', 'i', 'b', '6745', '747', '8329', '1481', 'b', '8949', 'n', '4803', '1359', '3533', 'f', '543', '3003', '6943']

Ex Output:
b, e, f, i, j, m, n, p, q


Ex Input:
['3127', '9253', '5667', '9453']

Ex Output:
-1


Ex Input:
['l', 'j', 'j', 'h', 'o', 'y', 'p', 'b', '8907', '9175', '7493', 'i', '7391', '7933', 'g', '2025', 'v', '797', 'a', 'f', '941', 'w', 'k', '7923', 'z', 'n', '1351', 'h', 'y', '171']

Ex Output:

a, b, f, g, h, i, j, k, l, n, o, p, v, w, y, z