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.

['8829', 'm', '5369', 'q', '5737', '7799', '5705', 'p', 'w', '1983', '4849', 'h', '6771', 'p', 'y', '1071', 'u', '6401', '7723', 'p']
h, m, p, q, u, w, y

['5463', '5683', 'w', '4071', '3997', 'i', '9677', 'q', 'l', 'v', 'w', '5325', '197', 'g', 'g', '3227', '3477']
g, i, l, q, v, w

['i', 't', '1549', '2399', '3263', '2435', '8525', '9711', '2417', '7997', 'z', 'z', '6785', '4341', 'w', '6749', 'v', '7677', 'z', 'm', '8343', 'j', '3373', 'a', '6135', '9057', '5991', '8227', '6431', 'p', '1179', '729', '2841', 'p', 'z', 'u', '8313', 'b', 'n']

a, b, i, j, m, n, p, t, u, v, w, z