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: ['3651', 'c', 'm', '7123', '2981', '9649', 'o', '2181', 'h', '8577', 'a', '5027', 'x', 'u', '1039', '347', '8219', 'c', '1063', '8885', 'f', 'd', '3067', '2509', 'i', 's', '5509', '2003', 'h', '8869', 'x', 'd', '5141', 'h', 'i', 'b', 'o']

SOLUTION: a, b, c, d, f, h, i, m, o, s, u, x

PROBLEM: ['7013', '8755', 'u', '9377', 'n', '6997', '507', '8557', '9745', 'g', '3019', '93', 'l', '1219', 'a', '393', '2573', 'q', 'b', '6101', 'e']

SOLUTION: a, b, e, g, l, n, q, u

PROBLEM: ['d', '8495', '8971', 'f', 'n', 'v', '897', 'f', '1299', '7957', 'f', '3871', 'u', '5199', '2515', '2823', '9683', '6363', '9699', 'b', '8847', '6431', 'h', '4033', 'v', '3469', 's', '1031', 'd', '9933']

SOLUTION:
b, d, f, h, n, s, u, v