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:
['3627', '2051', '3203', 'c', 'r', 'a', '1453', 'e', 'z', 't', '1093', '4651', 'a', 'f', '8159', '9623', 'l', 't', 'r', '6963', '7071', '8103', '3493', 'y', '2369', '609', '2011', 'f', '187', 'f', 'c']
answer:
a, c, e, f, l, r, t, y, z


question:
['5345', 'f', '6605', 's', 'q', 'w', 'p', 'o', 's', 'u', 'i', '7339', '8379', 'h', '9547', 'b']
answer:
b, f, h, i, o, p, q, s, u, w


question:
['7011', 'n', 't', '8983', '6241', 'u', 'l', '9689', 'o', 'm', '7701', '2263', 'k', '9009', 'u', '9095', '963', 'g', '8399', 'm', '5053', '5289', '6559', 'n', 'e', 'n', 'a', '7133', '271', '6667', 'p', 'x', 'b', 's', '2429', '3777', '2513', 'x']
answer:

a, b, e, g, k, l, m, n, o, p, s, t, u, x