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.

['n', 't', '2901', '9697', 'a', 'j', 'x', 'a', '4437', '2255', '2177', 's', '3173', 'j', 't', '5713', '4091', '4253', '5553', 'i', '4533', 'i', 'e', '6899', 's', '3541', '2139', '2705', 'm', 'u']
a, e, i, j, m, n, s, t, u, x

['h', '6865', '4019', '8571', 'y', '5575', '7835', '9537', 'n', '875', 't', 'a', 's', '2769', 'p', '1607', 'n', '4087', '961', '7869', '5085', '2131', '4867', 'j', 'h', 'y', '3105', '6609', 's', 'l', '3399', '5013']
a, h, j, l, n, p, s, t, y

['5159', '3869', '275', 't', '4039', 'i', '8573', 'f', 'u', '5489', '1751', 'v', '285', 'g', 'l', 'h', 't', 'a', '9445', 'o', '4419', 'c', 'k', '4045', 'l', 'x', 'w', 'g', 'x', '8583', '5179', '3965', '355', 'y', '6577', 'e', 'j', 'a', '3733', 's', '4391', '6155', '6773', '4767']

a, c, e, f, g, h, i, j, k, l, o, s, t, u, v, w, x, y