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:
['3043', 'r', 'm', 'i', '2653', 'i', '1703', '1125', '6299', '4863', 'n', 'h']
answer:
h, i, m, n, r


question:
['135', 'u', '3435', '2985', '9811', 'y', '4309', '9757', '905', 'd', 'g', 'q', '1457', 'l', 'o', 'u', '4517', '2333', '3327', '577', 'a', '4041', '8101', '6211', 'f', 'j', '1721', '7217', 'q', '7443', '8477', '3117', '7779', '9339', '8615', 'm', 'c', 'f', 'c', '8979', '7895', 'k', 'w', '1619']
answer:
a, c, d, f, g, j, k, l, m, o, q, u, w, y


question:
['9271', '6393', '6005', 'x', '2301', '3999', 'p', 'z', 'j', '1033', '7555', 'r', 'r', 'y', '8917', '5939', '4031', 'e', '8095', 'g', '6095', 'a', '4133', '6471', '2129', '8021', '1093', 't', '8805', '545', 'k', '3249', 'l', '1561', '9909', 's', '1963', 'o']
answer:

a, e, g, j, k, l, o, p, r, s, t, x, y, z