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:
['d', 'p', 'q', '5319', 'w', '4887', '6695', 't', '7711', 'l', '7597', 's', 'n', '1461', 'e', '9045', '1307', 'j']
answer:
d, e, j, l, n, p, q, s, t, w


question:
['v', '2989', 'z', '7843', 'e', '9923', 'y', 'b', '7611', 'u', 'u', '6227', '3145', 'w', '6451', 'g', '3129', 'o', 'r', 'z', '8349', 'u', 'h', 'd', 'g', 'a']
answer:
a, b, d, e, g, h, o, r, u, v, w, y, z


question:
['d', '7191', '7699', 'd', 'j', '6065', '1323', 'a', '3811', '33', 'k', '8265', '3219', '2189', 'a', 'y', 'z', '4663', '8875', 'l', 'd', '5093', '3205', 'r', 'e', 'q', '8035', 'b', 'v', '8163', '501', '453', 'q', '919', 'k', 'k', '6947', 'i', 'x', 'v', 'j', 'a']
answer:

a, b, d, e, i, j, k, l, q, r, v, x, y, z