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:
['3307', 'r', '2665', '3453', 'f', 'd', 'v', '3801', '3153', '3137', 'y', 'i', '9681', 'k', '9253', 'y', 'i', '8631', '2375', '5131', 'r', 'z', '8645', '595', 's', '6749', '2665', '709', '8203']
answer:
d, f, i, k, r, s, v, y, z


question:
['4397', '2685', '9539', '4343', '6697', '7693', 'g', 'c', '3587', '4691', 'j', '8931', '7397', '2103', '3431', 'u', 'l', 's', 'v', 'q', 'd', '1289', 'h', '1695', 'h', 'j', 'e', '1225', 'e', '7893', 'o', 'i', '3351']
answer:
c, d, e, g, h, i, j, l, o, q, s, u, v


question:
['8789', 'd', 'q', '9337', 'c', 'c', 'g', 'i', '1909', 't', 'd', 't', '3955', 'd', 'l', 'o', '4199', '3031', 'y', '8467', '1691', 'u', 'n', 'n', 'h', '2369', 'q', '6337']
answer:

c, d, g, h, i, l, n, o, q, t, u, y