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: ['j', '8797', 'i', '5443', 'i', 'f', '7593', 'u', 'h', '3251', 'l', '681', 'y', 'n', 'r', '1699', '1379', '8987', '6955', 'x', 'p', 'x', '553', 'q', '5679', 'q', 'w', '9007', 'r', '8945', '7351', 'a', 'v', 'k', '1309', 'v', 'i', '4161', 'a', 'q', '2919', '6917', '6845']

SOLUTION: a, f, h, i, j, k, l, n, p, q, r, u, v, w, x, y

PROBLEM: ['1233', '405', '8901', '7147', '8841', 's', 'v', '3131', 'p', 'd', 'y', '5873', '439']

SOLUTION: d, p, s, v, y

PROBLEM: ['q', 'f', '1753', 'p', '5821', 'm', 'j', 'd', '155', '717', 'g', 'k', 'e', 'f', '3019', '7587', 'm', '2081', '7775', '6931', '6619', '403', '625', 's', 'i', 'u', '1823', '7783', 'm', 'z', '9607', '635', '8433', '1003', 'd', 'd', 'g']

SOLUTION:
d, e, f, g, i, j, k, m, p, q, s, u, z