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: ['4993', 'n', '7115', 'f', 'd', 'q', '249', '3203', 'w', '5689', '4103', '7129', '603', 'e', 'z', '5571', '3241', '6029', '2721', '8451', 'o', '7841', 'p', '6271', 'r', 'b', '9481', '4045', 'v']

SOLUTION: b, d, e, f, n, o, p, q, r, v, w, z

PROBLEM: ['8451', 'x', '9965', '9303', 'm', 'f', '4205', 'y', 'n', '8521', '9995', 'z', 's', '3519', 'k', 'e', 'o', 'k', '9611', 'q', 'l', 'p', '3339', '4023', 'n', 'd', '8903', 'a', 'k', 'u', '4009', 'e', 'm', '989', '4495']

SOLUTION: a, d, e, f, k, l, m, n, o, p, q, s, u, x, y, z

PROBLEM: ['o', '7227', '433', '841', 'b', 'l', 'v', 'l', 'o', '4359', 'a', 'j', '1551', 'h', 'e', '8917', '41', '4353', 'l', '4161', '8561', 'j', '8975', '3915', '2123', '4537']

SOLUTION:
a, b, e, h, j, l, o, v