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: ['e', 'c', '4241', '2685', 'o', '9859', 'z', '2647', 'b', 'c', 'y', '1985', '5985', '5709', '6655', 'q', 'z', '9933', '6817', '6477', '1837', 'x', 'p', '9251', '3787', 'v', '5741', 'e', 'p', '493', '5949', '5519', 'v', 'g', '1403', 'z', 'h', 'z']

SOLUTION: b, c, e, g, h, o, p, q, v, x, y, z

PROBLEM: ['o', '9599']

SOLUTION: o

PROBLEM: ['5407', '7207', 'd', 'u', 'o', '5053', 'j', '3957', 'o', '7249', '2531', '6189', '3159', '8173', '113', '8339', '8685', 'i', '2705', 'b', 'n', 'w', '3639', 'c', '8205', '3035', 'j', 'a', '4685', '6767', '7597']

SOLUTION:
a, b, c, d, i, j, n, o, u, w