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: ['x', 'o', '8161', 's', '3653', 'v', 'c', 'e', '5353', 'h', '9145', '333', 's', '7689', '8277', 'a', 'o', 'h', 'z', 'w', '9297', 'w', '9383', '8963', 'k', 'x', 's', 'w', 'h', 'j', '5737', 'o', '2247', '3723', '2043', '4615']

SOLUTION: a, c, e, h, j, k, o, s, v, w, x, z

PROBLEM: ['4927', 'h', 'x', '4719', 'j', 'f', '7797', 'l', 'i', 'q', 'x', 'i', 'k', '3215', 'k', '1625', 'g', 't', 'i', 'w', 'n', '6659', '8355', '831', 'h', '9723']

SOLUTION: f, g, h, i, j, k, l, n, q, t, w, x

PROBLEM: ['9779', 'v', 'b', '2807', 't', '9625', 'q', '5127', '1475', 'l', '9821', '4875', '1323', '1851', '1607', 'p', 'i', '2955', '9295', 'a', 'y', '1473', 'u']

SOLUTION:
a, b, i, l, p, q, t, u, v, y