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: ['f', 'j', '9195', '3155', '2855', '5333', '5263', '9279', '687', 'e', '3055', '7233', '13', 'j', 'p', 'i', '8327', 'm', 'h', '3977', 'h', '7997', 'a', 'h', '4661', 'x', '8237', 'a', '5009', 'o', 'p', 'z', '2293', 'q', 'p', '5469', 'k', 'q', 'b', 'n', '1967', '4991']

SOLUTION: a, b, e, f, h, i, j, k, m, n, o, p, q, x, z

PROBLEM: ['l', '6819', '1029', '2925', '2361', '5545', '2151', '2681', 'f', 'p', '1263', '2875', 'b', '4665', 'f', 'g', 'p', '4829', '8453', 'z', 'l', '4219', '7517', '25', 'a', '5099', '3693', 'i', '1815', '1541', 'g', '7665']

SOLUTION: a, b, f, g, i, l, p, z

PROBLEM: ['q', 'f', 'd', '2619', 'y', '9691', 'a', '2663', '5781', 'g', 'x', 'p', 't', '4599', 'l', 'p', 'f', '1173', '3743', 'v', 'x', '5853', 'y', '747', 'q', 'a', '7015', '5153']

SOLUTION:
a, d, f, g, l, p, q, t, v, x, y