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: ['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: ['x', 'i', 'r', '6011', 't', 'f', 'b', 'i', '8367', '4051', '1459', 'f', '5583', '9609', 'l', 'q', 'g', '8443', 'o', '8697', '7053', '8325', 'k', '7021', 'q', 'm', '6899', '9981', '8985', 'i', 'j', '8043', 'k', '535', '7603', '7629', 'k', '2779', 'g', '2049', 'x', 'd', '8527', 'k', 'q']

SOLUTION: b, d, f, g, i, j, k, l, m, o, q, r, t, x

PROBLEM: ['7591', '7521', 'm', '1429', 'x']

SOLUTION:
m, x