TASK DEFINITION: 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.
PROBLEM: ['305', '95', 'e', 'q', 'e', '341', 'u', 'w', '5911', '6851', 's', 'u', '2355', 'd', '4151', 'w', '4421', '1129', '8065', 'k', 'q', '3649']

SOLUTION: d, e, k, q, s, u, w

PROBLEM: ['1595', '2915', 'o', 't', 'c', 'h', '3969', '5407']

SOLUTION: c, h, o, t

PROBLEM: ['1077', '8849', 'k', '7169', 'f', 'f', 'j', 'l', 'j', 'r', '3823', '3259', '4851', '425', 'r', '7763', 'v', 'l', '3955', 'a', '9783', 't', 'i', 'w', '5769', '7939', '2677', 'd', 'l', 's', 'c', 'z']

SOLUTION:
a, c, d, f, i, j, k, l, r, s, t, v, w, z

