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: ['a', 'p', 'y', 'l', 'l']

SOLUTION: a, l, p, y

PROBLEM: ['i', '1191', '5581', '2527', 'g', '9795', '519', 'u', '8389', '9793', 'k', '5733', '7125', '7835', 'j', '855', 'd', 'd', '6555', '3211', 'l', 'o', 'b', '523', 'x', 'j', '1707', '4161', '7171', 'h', 'h', 'm', 'h', '2443', 'e', '649', '951', 'n', 'h']

SOLUTION: b, d, e, g, h, i, j, k, l, m, n, o, u, x

PROBLEM: ['2339', 'u', '3153', '1939', 'p', 'u', '2323', 'h', '4075', 's', 'r', 'd', '9991', 'v', 'e', 'x', '4147', '3379', 'o', '7453', 'i', 'x', '1931', 'd', 'h', '6825']

SOLUTION:
d, e, h, i, o, p, r, s, u, v, x