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

['e', 'k', '7569', '6387', '4593', '2445', '345', '2905', 'h', '3119', '7001', 'x', 'a', '2943', '3635', 'l', 'q', 'z', 'g', '2657', '7849', 'i', '9413', 'm', 'e', '2951', 'd', '2963', 'b', 'u', 't', 'i', '1141', 'c', 'm', '8607', 's']
a, b, c, d, e, g, h, i, k, l, m, q, s, t, u, x, z

['1939', '903', '3751', 'x', 'n', 'r', '7559', 'e', 'i', '4265', 'r', 'h', '8371', '7721', 'w', '4205', '6989', '315', '2269', 'd', '8723', '6131', 'm', 'f']

d, e, f, h, i, m, n, r, w, x