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:
['8495', 'p', 'j', 'm', 'n', '9115', '1183', 'r', 'r', '8735', 'a', 'i', 'k', 'p', '8927', 'r', '9283', '9563', 'g', '2503', 'h', '1091', '5257', 'a', '3061', '2835', 'l', 'w', 'j', '7617', '8793', '7463', 'h', '8467', '7337', 'b', '4655', 'd']
answer:
a, b, d, g, h, i, j, k, l, m, n, p, r, w


question:
['5611', 'x', 't', 'p', '5711', '7079', '5251', '429', 'z', 'u', '8721', '9321', '79', 'i', '189', '3605', 'k', '445', 'r', 'k', 'o', '2189', '8521', '8849', '2651', 'm', '4149', '1577', '3085', '5275', '6413', '5265', '6089', 'r', 'f', '5013']
answer:
f, i, k, m, o, p, r, t, u, x, z


question:
['o', 'x', '6337', 'm', 'i', 'v', '7393', 'l', '4001', 'i', 'q', 'a', '7055', 'd', 'c', '9273', 'r', 'a', '8485', '9601', '9163', 'p', '4405', 'y', 'z', 'd', '8951', '1357', '5975']
answer:

a, c, d, i, l, m, o, p, q, r, v, x, y, z