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:
['219', '2065', '4045', 'k', 'n', 's', 'z', '7239', '1043', 'r', '2333', 'q', 'k', 'b', '2013', 'g', '6925', '9835', 'a', '5377', 'k', '8005', 'p', '9753', 'm', '201', '2353', 'f', 'n', '89', 'q', 'p', '7847', 's', 'l', '3359', '2269', 'v', 'm', '8247', '9665', 'u', 'w']
answer:
a, b, f, g, k, l, m, n, p, q, r, s, u, v, w, z


question:
['5293', '2211', 'r', 'j', 'x', 'y', 'u', 'n', 'r', 'l', 'v', '113', 'v', 'e', '1323', '6291', 'a', '7417', 'j', '4175', 'd', '855', 'z', '1123']
answer:
a, d, e, j, l, n, r, u, v, x, y, z


question:
['1687', '6923', 'c', 's', '5951', 'm', 'l', 'r', 'c', '4245', '8927', 't', '7907', '2971', '4331', '8703', '6851', 'b', '3399', '9149', '7835', 'q', 'z']
answer:

b, c, l, m, q, r, s, t, z


