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:
['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:
['d', 'a', '6931', 'c', 'u', 'z', '9713', 'v', 'm', 'e', 'k', 'o', '9705', 'a', '5373', 'c', '2983', '8097', 'h', '3039', 'g', 'f', 'n', 'v', '853', '8227', '7573', 'j', 'h', 'k', 'o', 'k', '8897', 'd', 'g', 'd', 'd', '4039']
answer:
a, c, d, e, f, g, h, j, k, m, n, o, u, v, z


question:
['6093', '5527', '3349', '3081', '7833', 'n', '4811', 'e', 'l', '3691', '8473', 'd', '3375', 'e', 'v', 't', '5093', 'a', 'g', '6591', 'f', 'r', 'p', '4733', 'g', 'a', 'c', '4677', '2481', 'n', 'i']
answer:

a, c, d, e, f, g, i, l, n, p, r, t, v