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:
['i', 'i', 'h', 'g', '5123', 'i', 'r', '3183', 'w', 'g', 's', '9777', '455', 'l', 'r', 'h', 'e', 's', 'v', '6823', '463', '9603', 'e', '947', '7071', 'c', '3373', 'j', 'w', 'm', 's', 's', '3483', '9567']
answer:
c, e, g, h, i, j, l, m, r, s, v, w


question:
['1367', 'h', '4153', '1587', 'h', 'b', 'n', 'u', 'n']
answer:
b, h, n, u


question:
['w', '3549', 'h', '8369', 'u', 'y', '5919', '8793', '941', 'e', '1527', '9011', '5637', '8115', 'k', 'r', 'n', 'h', 'y', 'h', '7335', 'm', 'r', 'n', 't', 'm', 'k', 'n', '3185', '7329', 'n', 't', 'o', '6621', 'x', 'p', '6613', '4575', '7049', '3159', 'h', '8761', 'p']
answer:

e, h, k, m, n, o, p, r, t, u, w, x, y