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.
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Question: ['a', 'w', 'm', 'g', 'c', '5475', '7391', 't', '1049', 'p', 'd', '1397', 'k', 'x', 'j', '2525', 'f', '741']

Answer: a, c, d, f, g, j, k, m, p, t, w, x


Question: ['2459', '3709', 'f', '8673', '9313', 'm', 'd', 'g', 'c', 'g', 'u', 'f', 'p', 'i', '8771', '3613', '9669', '6221', '1211', '8331', '2295', 'b', 'f', 'm', '1377', '9831', '1751', 'k', '4831', 'm', '2747', '3435', '4543', 'c', '1729', 'e', '7093', '397', 'm', '383', '2019']

Answer: b, c, d, e, f, g, i, k, m, p, u


Question: ['5431', 'x', '8369', 'l', 'u', 'u', 'n', '7757', '6277', 'c', 'k', 'l', '8239', '9865', '5865', '39', 'w', '807', '883', '1857', '1571', '3803', '4031', 'r', '627', 'g', 'g', '8765', '4205', '8653', 'o', 'n', '4451', 'y', '2631']

Answer:
c, g, k, l, n, o, r, u, w, x, y