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:
['2943', 'k', '8519', '9103', 'j', '2461', '1049', '2211', '8761', 'l', 'e', '8939', '6013', 'r', '9089', '5781', '5383', '5495', '6699', '7307', '2733', '933', '9865', 'g', '6471', '3179', 'm', '8231', 't', 'e', 'u', '9909', 'g', 'g', '9431', '6521', 'y', 'g', '1415', 'e']
answer:
e, g, j, k, l, m, r, t, u, y


question:
['a', '2579', 'f', '6787', '123', '225', '6499', '4419', 'o', '1785', '7981', 'z', 'b', '2441', '2821', 'o', 'k', '2747', 's', 'u', 'q', '3901', '7629', 'k', 'm', 'q', '6577']
answer:
a, b, f, k, m, o, q, s, u, z


question:
['k', 'o', '315', '9853', '8573', '1205', 'd', '3667', '2713', '3707', 'j', 'e', '4923', 'g', '1863', 'l', '7077', 't', 'y', 'c', 'b', '2397', '8261', 's', 'a', 'e', 'p', 'y', '6701', 'd', 'a', '8379', '6027', 'i', '3743', '133', '3937', 'q', '7125', '7295', 'e', '2151']
answer:

a, b, c, d, e, g, i, j, k, l, o, p, q, s, t, y