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: ['j', '6675', 'u', 's', '705', '8227', 'f', 'w', 'n']

SOLUTION: f, j, n, s, u, w

PROBLEM: ['j', 's', 'z', 'v', '5401', 'u', '8859', 'i', 'l', 'a', 'p', 'v', 'v', 'o', '3969', '4091', 'y', '6827', '1799', '5163', 'd', 'w', '4795', '5167', 'x', 'q', '2903', '1171', '5279', '449', '7901', 'u']

SOLUTION: a, d, i, j, l, o, p, q, s, u, v, w, x, y, z

PROBLEM: ['9733', 'z', '663', '4653', '1259', '249', 'd', 'm', 'y', '651', 's', 'e', 'g', '3627', 'l', '8769', 't', '395', 's', 'p', '8777', 'o', 'i', '6653', '5113', '7723', 'n', '6339', 'n', 'l', 'j', '7755']

SOLUTION:
d, e, g, i, j, l, m, n, o, p, s, t, y, z