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: ['747', '5385', '5313', 'p', '9581', 'r', '1339', '3919', 'e', 'e', '8057', '7739', 'i', 'e', '3311', '963', 'g', 'h', '7349', 'y', '1493', 'e', '3055']

Answer: e, g, h, i, p, r, y


Question: ['5431', 'o', 'u', 'l', 'f', 'd', 'r', '1479', '9357', 's', 'v', '6399', 'b', '7937', 't', '8497', 'r', '131', 'h', 'c', 'v', '8879', 'k', 'r', '4687', 'l', '1065', 'r', 'w', 'l', '3305', '461', 'q', 'h', 'b', 'e', 'e', 'w', '5999']

Answer: b, c, d, e, f, h, k, l, o, q, r, s, t, u, v, w


Question: ['p', 't', 'o', '4725', 'f', 'a', '6379', '5933', 'q', '3397', '6463', '9753', 'm', 'v', 'n', 'p', 'r', 'u', 'c', 'x', 's', '3323', '1599', 'g', '2535', 'u', '5347', 'h', 'y', '8239', 'o', 'w', 'i', '6725', 'l', '9921']

Answer:
a, c, f, g, h, i, l, m, n, o, p, q, r, s, t, u, v, w, x, y