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: ['5463', '5683', 'w', '4071', '3997', 'i', '9677', 'q', 'l', 'v', 'w', '5325', '197', 'g', 'g', '3227', '3477']

SOLUTION: g, i, l, q, v, w

PROBLEM: ['5075', '9169', '4659', '7605']

SOLUTION: -1

PROBLEM: ['d', '7191', '7699', 'd', 'j', '6065', '1323', 'a', '3811', '33', 'k', '8265', '3219', '2189', 'a', 'y', 'z', '4663', '8875', 'l', 'd', '5093', '3205', 'r', 'e', 'q', '8035', 'b', 'v', '8163', '501', '453', 'q', '919', 'k', 'k', '6947', 'i', 'x', 'v', 'j', 'a']

SOLUTION:
a, b, d, e, i, j, k, l, q, r, v, x, y, z

