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: ['4371', '9499', 'e', 'w', '9969', '8367', '2897', '1745', 'i', '7049', '9773', 'h', '9649', 'u', '4673', '8513', '8547', 'z', '1995', '7739', '2215', '171', 'c', '7527', '2479', 't', '5223', 'p', '2313', '3243', '2281', 'r', 'c']

SOLUTION: c, e, h, i, p, r, t, u, w, z

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: ['r', '1047', 'j', 'j', 'h', 'o', '4575', '4805', 'd', 'w', 'n', '6563', 'p', '7989', '6469', 'z', '1131', '4285', '379', 'q', 'o', '9167', '7843', 'w', 'i', 's', '1295', '5483', 'd', '4341', '6105', 'r', 't', '3217', 'b', 'w', 'l', '8457', '3773']

SOLUTION:
b, d, h, i, j, l, n, o, p, q, r, s, t, w, z