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:
['m', '3809', 'l', 'k', '1929', '7963', 'n', 'u', '2125', 'g', 'o', '8325', 'o', 'h', 'y', '3025', 'e', 'e', 'c', 'x', '8445', '4979', 'z', 'f', '4201', '4765', 'g']
answer:
c, e, f, g, h, k, l, m, n, o, u, x, y, z


question:
['7123', 'm', 'h', '4065', 'c', 'n', '187', '3899', 'r', 'k', '2071', '9481', '6277']
answer:
c, h, k, m, n, r


question:
['3185', 'n', '9627', '5889', 'v', '1045', 't', '3175', '2779', 'p', 's', 'u', '4657', '4263', 'k', 'r', '5631', 'y', '5475', 'e', 'i', '5949', 'z', 'r', 'r', 'r', 'r', 'c', '2375', 'g', '3669', 'l', '5199', 'm', 'c', 'y', 't', '1399']
answer:

c, e, g, i, k, l, m, n, p, r, s, t, u, v, y, z