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: ['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: ['k', 'z', '303', 'a', 'f', 'q', 'i', '1475', '3453', 'd', 'w', '4037', 'z', 'h', 'k', '3547', '1561']

SOLUTION: a, d, f, h, i, k, q, w, z

PROBLEM: ['u', '363', 'w', '5321', '5345', 'p', 'g', '8287', '5081', '3839', '5015', '5217', '5031', '4119', 'd', '8371', 'd', 'f', '6245', '3059', '4591', 'g', 's', '7841', '757', '1257', '537', 'f', '9791', 'a', '5935', '6487', 'a', '605']

SOLUTION:
a, d, f, g, p, s, u, w