instruction:
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:
['1653', '3177', 'b', '2785', '2515', 'd', '5513', '5599', '2947', 'v', '2771', '5697', '2913', '4161', '5939', '2655', '6787', '9851', 'q', '3199', 'x', '1305', '9423', '9117', '4821', 'j', '7963', 'i', 's', '469', 'r', 'w']
answer:
b, d, i, j, q, r, s, v, w, x


question:
['5859', 'x', 'z', 'v', 'l', 'z', 'g', 't', 'x', '341', '7023', '4937', 'b', 'n', 'y', 't', 's', '1369', '4461', 'f', '1315', 'l', '5221', '6583', 'h', 'j', 't']
answer:
b, f, g, h, j, l, n, s, t, v, x, y, z


question:
['4933', 'w', 'e', '5495', '4577', 'k', 'e', '9065', 'a', 's', '7789', 'g', 'l', 's', '3131', 'g', '3419', '5267', 'j']
answer:

a, e, g, j, k, l, s, w


