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: ['u', '1805', 'l', 'l', '5449', 'r', '4471', 'a', 'u', 'c', 'q', '6463', '6717', '7025', '9359', 'q', 'h', '1989', '5497', 'h', 'd', 'c', '135', '5737', '1235', 'v', 'u', 'g', 'p', 't', '9223', '8289', '4489', 'n']

SOLUTION: a, c, d, g, h, l, n, p, q, r, t, u, v

PROBLEM: ['1197', '305', 's', '1113', 'n', '2207', 'e', '227', '2833', '607', '3049', 'v', '4615', 'a', 'k', 'r', 's', '3571', 'f', '4215', 'f', '8985', '5559', '4111', 'u', '1433', '1943', '8831', 'w', 'x', 'o', '9023', 'u', 'y', 'p', 's', 'h', '8877', 'p', 'n', '8903', '5811']

SOLUTION: a, e, f, h, k, n, o, p, r, s, u, v, w, x, y

PROBLEM: ['9425', 'l', 'c', 'n', '5925', '2543', '3935', 'c', '7533', 'j', 'q', '3775', '5897', '9435', '69', 'e']

SOLUTION:
c, e, j, l, n, q