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:
['t', 'h', '6141', 'g', 'f', 'z', 'n', 'b', 'k', '9059', 'y', 'p', '4289', '2683', 'a', '3267', 'w', 'p', 't', '3623', '7759', 'a', 'o', 'm', '9815', 'q', 'u', '8051', '6871']
answer:
a, b, f, g, h, k, m, n, o, p, q, t, u, w, y, z


question:
['x', 'u', 'm', '8089', '9985', 'e', '2927', 'n', '7085', 'q', 'v', 'f', 'p', '5079', '3339', '7871', 'h', '7389', '733', 'e', '3387', 'b', 'x', 'z', '2039', 'u', '59', '5031', '8115', '5447', '3045', 'x', '6591', '9561', '4315']
answer:
b, e, f, h, m, n, p, q, u, v, x, z


question:
['3417', 'w', '6771', 'e', 'p', '9567', '589', 'a', 't', '6623', 'v', 'm', '4803', '5541', 'v', 'v', '6427', '6515', 'a', 'x', '3363', 'g', 'k', '9683', 'q', 'h', 'q', 'l', 'x', 'a', 'o', '8093', '9455']
answer:

a, e, g, h, k, l, m, o, p, q, t, v, w, x