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: ['w', '743', '5757', '8731', 'k', 'p', '317', 'n', 'x', '5649', 'l', 'm', 'c', '2499', 'l']

SOLUTION: c, k, l, m, n, p, w, x

PROBLEM: ['5785', 'c', 'f', '7087', 'd', '9225', 'm', 'g', '4639', '7165', '3445', '3813', 'p', 'i', '719', 's', 'g', '6423', '9563', 'w', 'm', '8659', '8809', '4105', '3923', '465', '5637', '5547', 'h', 'v', '9453', '4009']

SOLUTION: c, d, f, g, h, i, m, p, s, v, w

PROBLEM: ['411', 'o', '1419', 'g', '2283', '7753', '143', '6413', 'r', 'p', '9351', '6247', 'q', '8913', '455', '3581', '7703', 'r', '8153', 'a', 'q', '2659', 'e', '9211', 'x', 'p', 'i', 'l', '577', '6859', 'r', 'v', 'z', 't', '3239', '4161', '5371', '2477', '7993', 'q', 'c', 'h', '265', '163']

SOLUTION:
a, c, e, g, h, i, l, o, p, q, r, t, v, x, z