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: ['459', '1729', 'b', 'c', '9619', '4461', '4347', '6733', 'i', '3631', 's', 'j', 'i', 'r', '5293', 'q', '7397', '4309', 'c', 'n', 'k', '197', 'q', '8139']

SOLUTION: b, c, i, j, k, n, q, r, s

PROBLEM: ['9271', '6393', '6005', 'x', '2301', '3999', 'p', 'z', 'j', '1033', '7555', 'r', 'r', 'y', '8917', '5939', '4031', 'e', '8095', 'g', '6095', 'a', '4133', '6471', '2129', '8021', '1093', 't', '8805', '545', 'k', '3249', 'l', '1561', '9909', 's', '1963', 'o']

SOLUTION: a, e, g, j, k, l, o, p, r, s, t, x, y, z

PROBLEM: ['e', 'q', '9427', '585', '7565', '245', '5385', 'g', 'm', 'b', 'x', 'q', 'b', '4339', '4701', '5797', '1303', 'g']

SOLUTION:
b, e, g, m, q, x