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: ['j', 's', 'z', 'v', '5401', 'u', '8859', 'i', 'l', 'a', 'p', 'v', 'v', 'o', '3969', '4091', 'y', '6827', '1799', '5163', 'd', 'w', '4795', '5167', 'x', 'q', '2903', '1171', '5279', '449', '7901', 'u']

Answer: a, d, i, j, l, o, p, q, s, u, v, w, x, y, z


Question: ['3395', '7471', 'n', '9537', '1255', '1997', '3085', '4863', '9797', '4275', 'k', 'f', '8973', '3939', 'p', 'q', '4977', '6231', '8745']

Answer: f, k, n, p, q


Question: ['m', 'y', '8813', '8937', '5873', '209', 'c', '1435', '1777', 'q', 'i', 'q', 'g', 'u', 'p', '6371', '443', '1147', 't', '3867', 'r', '6043', 'n', '2401', 'o', 'c', '9947', 'w', 'l', 'y', '7609', 't', 'b', '1879', 'n', 'w', 'f', '9665', '9095', '9035', '9591', '9351', 'r', 'w', '9547']

Answer:
b, c, f, g, i, l, m, n, o, p, q, r, t, u, w, y