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', 'v', '1099', 'y', '1313', 's', '181', 'u', 'e', 'u', '8435', '4125', '8661', 'c', '4605', 'f', 'x']
c, e, f, p, s, u, v, x, y

['y', 'g', '107', '4899', '6357', '9777', 'k', '1865', '7029', 'q', 'x', '7051', 's', '6125', '4285', '2731', 'z', 'a', '737', '6137']
a, g, k, q, s, x, y, z

['r', '1139', 'n', 'b', '3673', '8947', 'g', '427', '649', 'd', '1533', '8063', '5221', 'n', '6463', '5547', 'a', 'n', '7193', 'f', 'q', 'a', '3031', '1211', 't', '6339', '999', 'l', '1647', 'b', '4131']

a, b, d, f, g, l, n, q, r, t