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.

['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']
a, c, f, i, m, n, p, r, t, u, v, w, y, z

['4653', 'e', 'c', 'j', '6739', '3963', 'q', '4649', 'v', 's', 'j', '9757', '8075', '6253', '4365', 's', '9101', 'd', '6989', 't', '5687', '7389', '139', '4029', '5073', 'q', 'e', '2455', '1075', 'j', '1329', 'l', '4689', 't', 'z', '4179', 's', 'l', 'w', 'n', '6569', '8907', 'v', '605', 'y']
c, d, e, j, l, n, q, s, t, v, w, y, z

['6569', 'z', '5599', 's', 'y', '1497', '1861', 's', 'j', '4357', '7079', 'a', '9989', 'h', '4309', 'i', 'd', '2957', 'l', 'o', '7423', 'm', 'e', '5325', '5985', 'z']

a, d, e, h, i, j, l, m, o, s, y, z