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.
--------
Question: ['9403', '9881', '8391', 't', '1793', 'w', 'x', 'y', '6383', 'j', 'r', '5323', 'r', 'l', 'e', 'u', '7193', '2309', '837', 'z', 'w', 'n', '4427', '8269', '6333', 'a', 'p', '1933', '8497', '2665', '1349', '6807', '9009', 'b']

Answer: a, b, e, j, l, n, p, r, t, u, w, x, y, z


Question: ['o', 'z', 'h', '3965', 'n', '3009', '173', '997', '3987', '5799', '2331', 'p', 'x', '897', '8213', '451', 'u', 't', 't', '9917', '4501', 't', 'c', 'i', 'w', 'w', 'u', '2977', 't', 'b', '4161', '9281', 'w', 'f', '3137', '5745', 'e', '673', '6363', 'h', 'q', 'x', 'm', '9505']

Answer: b, c, e, f, h, i, m, n, o, p, q, t, u, w, x, z


Question: ['7359', 's', 'j', '539', 's', 'f', '2159', '3707', 'u', '9911', 'u', '4909', 'n', '8313', '4485', '213', 'y', '4039', 'o', 'x', 'x', '8451', '9495', '9685', 'q', 'w']

Answer:
f, j, n, o, q, s, u, w, x, y