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:
['3191', '2655', '239', '2585', '3369', '7815', '5919', '8269', '5633', 'x', '8085', '2909', 'y', '2465', 'i', '1579', 'u', '2371', 'l', '1949', '51', 'e']
answer:
e, i, l, u, x, y


question:
['s', 's', '3619', '6051', 'h', '213', '3937', 'v', 'p', 'y', '8449', '9337', '5327', 'a', 'a', 'w', '3985', 'n', 'm']
answer:
a, h, m, n, p, s, v, w, y


question:
['c', '4825', 'c', '8521', 'p', '1025', 'z', 'w', 'a', 'd', '9757', '4485', 'g', 'h', '6437', '8443', '257', 's', '6599', '7511', 'n', '9511', 'z', 'j', '853', '487', 'm', 'n', 'g', 'x', '9683', '2175']
answer:

a, c, d, g, h, j, m, n, p, s, w, x, z