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: ['7653', 'n', '697', '4565', 't', '7275', '2429', '1365', '7059', 'o', '8053', 'j', '2837', '957', '851', 'z', 'd', 'd', 'y', 'c', '7467', 'o', 'i', '9519', 'q', 'g', '7911', 't', 'g', '3439', '5821', '8433', 'k', 'z', 's', 'g', '685', 'i', 't', 'r', '6881']

SOLUTION: c, d, g, i, j, k, n, o, q, r, s, t, y, z

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

SOLUTION: c, h, o, t

PROBLEM: ['h', 'x', '4599', '883', 'j']

SOLUTION:
h, j, x