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: ['u', '1343', 'd', 'c', '9567', 'e', 'd', 'y', 's', '4199', '3217', '2937', '9345', 'd', 'l', '9875', '5987', 'p', '2585', '5843', '9643', '2423', 'e', 'l', 's', '3503', 'b', 'w', '9685', 'p', '6055', 'k', 'e', 'e', 't', '865', '6071', 'j', '3439', 't']

SOLUTION: b, c, d, e, j, k, l, p, s, t, u, w, y

PROBLEM: ['2697', 's', '8733', 'n', '5871', 'f']

SOLUTION: f, n, s

PROBLEM: ['m', '1613', 'k', '2189', '4711', 'h', 'k', 't', 'y', '1669', 'w', '6049', '9531', 'a', '5443', 'n', '1037', '849', 'b', 'r', '4889', 'f', '1313', 'j', '1489', 'g', '1593', 'n', '9967', '2255', '6097', 'r', 'b']

SOLUTION:
a, b, f, g, h, j, k, m, n, r, t, w, y