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: ['o', 'c', '6469', 'x', '8815', '4441', '6193', 'u', 'm', 'a', '9879', 'p', '8335', 'c', 'z']

SOLUTION: a, c, m, o, p, u, x, z

PROBLEM: ['7155', 'y', '145', '7147', 'u', '8453', 'd', '3693', '6471', '5289', 'n', 'p', '8289', '2929', '199', 'e', '8377', '8937', '5315', 't', 'l', '7715', 'c', 'y', 'f', '9999', 'p', '3655', '5489', 'q', '2321', '9881', '2265', 'n', 'v', '455']

SOLUTION: c, d, e, f, l, n, p, q, t, u, v, y

PROBLEM: ['2205', '2845', '3589', 'e']

SOLUTION:
e