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:
['9223', 'w', '8631', '4453', '9975', 'y', '9747', 'g', '7077', '2593', '6015', 'n', '7345', 'i', '7807', '299', 'q', '3629', '2545', 'k', 'm', 'q', '5155', '5633', 'x', 'q', 'i', '27', 'f', '7919', 'p', '4835']
answer:
f, g, i, k, m, n, p, q, w, x, y


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:
['b', 'i', '6135', '3839', '7257', 'u', 'd', '3391', 'y', '2907', 'g', 'j', '8951', 'u', 'q', '5691', '71', '8767', '4207', '8085', 'b', 'o', 'v', 'w', 'p', '3013', 'e', 'm', 'b', 'g', 'u', '4981', 'q', 'c', '1673', 'x', '4305', 'm']
answer:

b, c, d, e, g, i, j, m, o, p, q, u, v, w, x, y