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:
['f', 't', '2135', '8397', '6361', '389', '2253', 'x', 'p', '4833', '5785', 'x', '1811', '9639', '5739', '175', '3231', '5931', 'r', 'c', 'g', 'h', 'p', '909', 'p', '587', 'a', 'a', 'h', 'q', 's', '5945', '4911', 't', 'h', '7517', 'p', '3177', 'h', 'u', '3577', '7055', 'l']
answer:
a, c, f, g, h, l, p, q, r, s, t, u, x


question:
['p', 'f', 'h', '1977', '6221', 'i', 'a', 'l', '5225', '8059', 'c', 'w']
answer:
a, c, f, h, i, l, p, w


question:
['7939', '2869', 'w', '1529', '1619', '4591', '5473', 'b', 'o', '699', '2199', '6393', '3647', '655', '4307', 'y', '1633', '3981', '9253', 'o', 'u', 'w', '43', '5327', '6555', 'q', 'h']
answer:

b, h, o, q, u, w, y