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: ['9223', 'w', '8631', '4453', '9975', 'y', '9747', 'g', '7077', '2593', '6015', 'n', '7345', 'i', '7807', '299', 'q', '3629', '2545', 'k', 'm', 'q', '5155', '5633', 'x', 'q', 'i', '27', 'f', '7919', 'p', '4835']

SOLUTION: f, g, i, k, m, n, p, q, w, x, y

PROBLEM: ['5957', 'd', 'i', 'b', 'e', '5565', 'c', 'i', '2919']

SOLUTION: b, c, d, e, i

PROBLEM: ['6549', 'm', '6071', '7979', 't', '7847', 'o', '305', '7239', 'f', '7237', 'u', 'u', '1375', 'm', 'g', 'x', 'w', 'f', 'u', 'l', '1555', 'y', '5715', '4441', 'r', '4979', 'm', '9625', 'z', '433', 'z', 'i', '8077', 'i', 'z']

SOLUTION:
f, g, i, l, m, o, r, t, u, w, x, y, z