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: ['z', 'h', '2065', '6773', 'v', '151', '8957', 't', 'l', 'j', '7867', 'v', '799', '9009', '4317', 'm', '6921', 'r', '1245', '5637', 'x', '4465', 'f', 'y', '3549', 'e', 'f', 'm', 't', '6281', '4241', '3415', 'z', 'g']

SOLUTION: e, f, g, h, j, l, m, r, t, v, x, y, 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: ['1439', 'i', 'a', '9403', 'm', '3671', 'l', 'b', 'd', 's', '4449', 'c', 'j', '879', 'a', '4673', '5117', '1163', '1843', '8395', '1891', '3901', '7805', '5097', '6895', 'z', '9475', 'k', 'o', '1979', '1759', '5613', '7353', 'l', 'j', '1769', '2407', 'a', '9283', 'j', 'l', '7951', '8131']

SOLUTION:
a, b, c, d, i, j, k, l, m, o, s, z