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:
['2103', '7937', 'v', '7641', '6609', '269', '4463', '4333', 'c', '8407', '4883', '6283', 'a', '8643', '3365', '1929', 'v', 'o', '2107', '7453', '9157', '5581', '5187', 'f', 'k', '8227', '6295', 'b', 'y', '4995', '1187', 'k', 'n', 'p', 'z', '8165', 'n', '7345', 'l']
answer:
a, b, c, f, k, l, n, o, p, v, y, z


question:
['h', 'b', '9601', 'h', 'h', 'h', '8099', '8265', 'i', 'd', '8791', 'p', '8059', '4309', '501', '2581', '9837', '157', '4785', '5925', 'q', '8491', '4779', 'r', 'l', 'k', '3679', 'v', 'g', 'g', '9731', '1909', '9783', 'f', '4293', '5009', 'o', '3057', '3157', 'c', '5587', 'b', 'f', 'd', 'k']
answer:
b, c, d, f, g, h, i, k, l, o, p, q, r, v


question:
['i', '8487', '4701', 'n', '6577', 'k', '7789', '3825', '9395', 'u', '7793', 'c', '5855', '9315', '8675', 'p', 'k', 'y', '3785', 'v', '9947', 'q', 'y', '8589', 't', '7465', '4227']
answer:

c, i, k, n, p, q, t, u, v, y


