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: ['s', 'w', 'c', '4137', 't', '2437', '349', 'h', '4539', 't', 'b', 'y', 'q', 't', '9087', 'c', '9489', '6285', '6247', '8353', 'n', 't', '8661', 'p', 'z', 'p', '773', 'w', 'q', '8081', 'r', 'u', 'z', 'k', 'a', 'b', '7513', '5549', '5325', '1101', 's', '6507', '3317']

SOLUTION: a, b, c, h, k, n, p, q, r, s, t, u, w, y, z

PROBLEM: ['6495', '2259', '8213', 'm', 'y', '3377', 'q', 'i', '1299', 's', 'w', '4331', 'h', '5459', '4059', '6637', '8069', '5367', '6025', 'l', 'v', '4503', 'd', 'x', 'w', '5067', '9019', 'd', '7919', '7299', 'v', '8957', 'v', '5341', '2617', '8169', 'n', 'y']

SOLUTION: d, h, i, l, m, n, q, s, v, w, x, y

PROBLEM: ['f', 'e', 'j', '5277', '2047', 'o', '7093', 'd', '1169', '4787', '4451', 'i', 'd', '2889', '9599', 'o', 'b', 'j', '4365', '9049', 'a', '2025', '6715', '9787', '619', 'b', '3769', 'v', 'j']

SOLUTION:
a, b, d, e, f, i, j, o, v