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:
['5553', 'f', '3881', '8867', 's', 'd', 'a', '375', '7889', '3949', '2905', 'w', 'q', 'q', 'd', '4203', 'i', '2601', 'y', 'p', 'k']
answer:
a, d, f, i, k, p, q, s, w, y


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:
['1403', '8661', '5385', '6065', 'r', '8523', '6295', 'w', 'u', '8677', '107', '2589', 'g', '3395', '927', 'x', '1157']
answer:

g, r, u, w, x