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', '9575', '8995', 'm', 'o', '3015', '4005', '6909', '7195', '3361', 'j', '5253', '9523', '8879', '5861', 'e', 'y', 'e', '1525', 'i', '807', '8469', '3333', '4017', '2237', '3387', 'o', '643', 'p', '7129', '6243', 'y', '4913', 'z', 'f', '6909', 'f', '4347', '7227', 'o', 's', '9909', '8611']

SOLUTION: e, f, i, j, m, o, p, s, y, z

PROBLEM: ['f', '3409', 'i', '4147', '1745', '6007', 'l', 'd', 'i']

SOLUTION: d, f, i, l

PROBLEM: ['z', '921', '1467', '9349', 'y', 'h', '7719', 'm', '3829', 'q', 'c', 'y', '6991', '105', 'v', '5029', 'x', '1359', 't', '4003', 'u', 'n', 'g', '3861', 'r']

SOLUTION:
c, g, h, m, n, q, r, t, u, v, x, y, z