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: ['3223', 'h', 'w', 'f', 'y', '1667', '8843', '8759', '9203', '3305', '3549', '5507', '6251', 't', '8319', '9121', '6643', 'u', '4273', '4429', '7543', '7909', '789', '9183', '5729', 'd', '7063', 'b', '6677', 'w', 'x', 'x', 'z', '769', 'p', 'd', 'h']

SOLUTION: b, d, f, h, p, t, u, w, x, y, z

PROBLEM: ['3505', 'x', '2025', 'b', 'c', '8749', 'x', 'f', 'p', '2371', '2431', 'x', '8397', '3023', '6911', '7203', 'e', '7003', 'e', 'l', 'e', 'r', 'w', '4847', 'v']

SOLUTION:
b, c, e, f, l, p, r, v, w, x