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:
['2741', '2541', '8943', 'l', '4047', '2211', 'p', 'e', 't', '7645', '9771', 'f', '5063', '2303', '6097', '5089', 'd', 'e', '1409', '3125', '2171', 'g', '1247', '4045', 'v', 'h', 'u', '2587', '5207', '5553', 'g', 'd', '6891', 'e', '2471', '2435']
answer:
d, e, f, g, h, l, p, t, u, v


question:
['6143', '9073', 'h', '1459', 'q', '5799', '6555', '525', '7921', '5041', '3273', '383', 'd', '9075']
answer:
d, h, q


question:
['m', '4239', '311', 'a', 'u', '3053', 'n', '4143', 'n', 'r', '9101', '4619', 'l', '1455', '7233', 'a', '2225', 'e', '7613', 'f', '1375', 'm', 's', '1967', '3801', '301', 't', '7691', '3531', '6773', 's', 'y', '5681', '3435', '7949', '5165', '8557', '8363', '5361', '1593', '3291', '2087', '295', '3975']
answer:

a, e, f, l, m, n, r, s, t, u, y