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:
['v', '5433', 'v', '6749', '7491', 'i', 'm', 'e', '5815', '8423', '833', '7359', 'm', 'i', 'f', 'u', 'p', 'j', 't', '3171', '6165', 'q', 'a', '9475', 'm', 'q', '5995', '8443']
answer:
a, e, f, i, j, m, p, q, t, u, v


question:
['4653', 'e', 'c', 'j', '6739', '3963', 'q', '4649', 'v', 's', 'j', '9757', '8075', '6253', '4365', 's', '9101', 'd', '6989', 't', '5687', '7389', '139', '4029', '5073', 'q', 'e', '2455', '1075', 'j', '1329', 'l', '4689', 't', 'z', '4179', 's', 'l', 'w', 'n', '6569', '8907', 'v', '605', 'y']
answer:
c, d, e, j, l, n, q, s, t, v, w, y, z


question:
['b', 'd', 'f', '9295', 'e', 'o', 'o', 'x', '7389', 'i', 'b', '2195', 'o', '8947', 'd', 'n', 'j', 'c']
answer:

b, c, d, e, f, i, j, n, o, x