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: ['i', 'i', 'h', 'g', '5123', 'i', 'r', '3183', 'w', 'g', 's', '9777', '455', 'l', 'r', 'h', 'e', 's', 'v', '6823', '463', '9603', 'e', '947', '7071', 'c', '3373', 'j', 'w', 'm', 's', 's', '3483', '9567']

SOLUTION: c, e, g, h, i, j, l, m, r, s, v, w

PROBLEM: ['f', 'w', 'y', 't', '5269', '9989', 'p', 'v', '6609', 'v', 'c', 'q', 'm', '6565', '189', 'm', '3617', 'b', '9147', '665', 'v', '5989', '1511', '3123', '6667', '4661', '185', 'b', '3405', 'b', '6027', 'n', '6973', '505', 'g', '815', '3439', '2069', '291', 'j', 'f', '1121', '8009', 'm', '8353']

SOLUTION: b, c, f, g, j, m, n, p, q, t, v, w, y

PROBLEM: ['8879', '7051', '8987', '6631', 'k', '7259', '949', '953', 'f', 'k', 'h', '7951']

SOLUTION:
f, h, k