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: ['4925', '9943', '7935', '4387', '2449', '5797', 'i', '1517', 'w', 'e', '9525', 'y', 't', 'e', '2793', 'v', '9897', '8709', '7247', 'o', 'f', '5549', 'q']

SOLUTION: e, f, i, o, q, t, v, w, y

PROBLEM: ['9025', '3259', '4863', 'u', '6443', '9931', '627', 'x']

SOLUTION: u, x

PROBLEM: ['4877', 't', '9515', 'v', 'm', 's', '7863', '445', 'w', 'z', 'e', 'k', '2523', '165', 'j', '8627', '8021', 'b', 'e']

SOLUTION:
b, e, j, k, m, s, t, v, w, z