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: ['p', '2923', 'e', 'k', '5433', '605', '5079', 'k', 'p', 'x', '4845', '4099', '6795']

SOLUTION: e, k, p, x

PROBLEM: ['u', '635', '5249', '9457', 's', '9317', '9407', 'l', 'w', '9705', 'k', '429', '5489', 'e', 'd', '2457', 'o', '4665', '1675', 'l', 'y', 's', 'o', 't', '4285']

SOLUTION: d, e, k, l, o, s, t, u, w, y

PROBLEM: ['2711', 'z', '6171', '7661', '6937', '5443', '3495', '3895', '8761', '6027', '9771', '2587', 'j', 'j', 'r', '2693', '8653', '8121', '1737', '2449', '5749', '6905', 'w', '8827', '3155', 'r', '5797', 'g', '111', '4711']

SOLUTION:
g, j, r, w, z