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: ['f', 'a', 'r', '4009', 'k', 'a', 'g', '7725', 'v', 'b', '6705', 'a', '6583', '3159', 'c', 'w', 'x', 'h', '7625', 'p', 'y', '5645', 'k', 'r', 'j', '4175', 'r', '3103', '8631', '5999', 'p', 'g', 'h']

Answer: a, b, c, f, g, h, j, k, p, r, v, w, x, y


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: ['l', '419', '5993', 'b', '7595', 'g', 'j', '4437', 'q', 'k', 'q', 'w', '2835', '7121', 'u', 'i', 'c', '3827', 'r', 'v', '8025', '653', 'f', '2507', 'p', 'o', '6669', '2295', 'p', '787', '7089', 'g', 'z', '1163', '5881', 'z', '8335']

Answer:
b, c, f, g, i, j, k, l, o, p, q, r, u, v, w, z


