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.

['u', 'd', '4193', '5687', 'p', 'r', '7787', 't']
d, p, r, t, u

['2181', '7019', 'l', 'z', 'z', 'y', '1245', '4179', '6951', '7249', '2723']
l, y, z

['705', 'l', '4675', '9123', 'f', 'c', 'f', '1175', 'r', 'a', 'o', '2909', 'r', '9851', '2213', '8403', '4765', '9425', '4321', '3433', 'p', '6463', '2295', '3847', '8267', 'j', 'g', '101']

a, c, f, g, j, l, o, p, r