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: ['4045', '4739', 'd', 'e', '6789', 'e', 'q', '4909', '9511', 'h', '9543', '6725', 'a', '3683', 'q', 'k', 'd', 'q', 'z', 'b', '3245', '9877', '9155', '7751', 'e', '1015', '2379', 'f', 'y', '1121', '9801', 'c', 'h', 'l', 'f', '67', 'v', 'v', 'y', 'c', '3871', 'v', '5893', 'a']

SOLUTION: a, b, c, d, e, f, h, k, l, q, v, 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: ['n', '2375', '2791', '6857', '6535', 'y', 'u', '6521', '9353', 's', 't', '1433', '1221', 'v', '5507', '2285', '4131', '3325', '9197', '6015', '3527', '1743', '7807', 'x', 'b', '8415', '4253', '3741', 'o', '7087', '3303', 'h', 'f', '4179', 'z', '1651', 'v', 'm', 'n', 'k', 'z', 'h']

SOLUTION:
b, f, h, k, m, n, o, s, t, u, v, x, y, z