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: ['h', 'v', '1263', 'y', '3299', 'd', 'a', 'h', 's', '2007', '7597', '1015', 'k', '6643', '6959', 'g', 'u', 'd', '5737', 'n', 'z', 'y', 'b', 'g', '9059', '7349', 'j', 'w', 'i', 'z', 'p', '5809', 'x', '4421', 'g', '6399', '3965']

SOLUTION: a, b, d, g, h, i, j, k, n, p, s, u, v, w, x, y, z

PROBLEM: ['2505', '4199', 'e', '5433', '8795', 'q', 'i', '9357', 'o', '257', '8235', 'b', '1339', 'w', '1463', 'm', '277', '3211', '3863', 'r', 'm', 'i', '5793', '7451', '4787', '4739', 'k', 't', 'o', '7453', '9385', 'v', 'l', 'y', 'f', 'r', 'p', 'w']

SOLUTION: b, e, f, i, k, l, m, o, p, q, r, t, v, w, y

PROBLEM: ['n', '8211', '7113', '911', '1109', 'm', '3101', 'b', '6463', '4141', '6791', 'j', '6817', 't', '3537', 'o', '9493', '6389', '1395', 'p', '5631', '1365', '6671', 'r', '9659', 'a', 'd', '3157', '8863', '8643']

SOLUTION:
a, b, d, j, m, n, o, p, r, t