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', 'p', '7899', 'u', '971', '7289', 't', '5217', 'k', 'z', 'y', 'y', '6905', '9499', '4085', 'x', '955', 'v', 'j', '9049', '7927', '1757', '193', '2181']
j, k, p, t, u, v, x, y, z

['7653', 'n', '697', '4565', 't', '7275', '2429', '1365', '7059', 'o', '8053', 'j', '2837', '957', '851', 'z', 'd', 'd', 'y', 'c', '7467', 'o', 'i', '9519', 'q', 'g', '7911', 't', 'g', '3439', '5821', '8433', 'k', 'z', 's', 'g', '685', 'i', 't', 'r', '6881']
c, d, g, i, j, k, n, o, q, r, s, t, y, z

['1649', 'l', 'i', '5901', 'o', 'g', '1197', 'a', '9327', '9835', '1095', 'k', '4489', '9149', 'o', '3095', 'z', 'u', 'y', '561', '7419', 't', 'j', '8763', 'v', '339', 'y', 'w', 'v', 'v', '1867', 'd', 'r', 'w', 'h', 'j', '1531', '3841']

a, d, g, h, i, j, k, l, o, r, t, u, v, w, y, z