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: ['g', 'h', 'g', 'g', 's', 'h', '2849', '2705', '1185', 'x', '5789', '8221', 'e', 'x', 'g', 'b', '4903', 'q', '1563', 'r', 'k', 't', '9047', 'p', 'p', '9397', 'u', '7473', 'f', 'o', 'y', '1957', '1039', '9905', 'i', '4829', 'q', 'w', 'k', 'p', 't', '563', 'g', 'l']

SOLUTION: b, e, f, g, h, i, k, l, o, p, q, r, s, t, u, w, x, y

PROBLEM: ['699', 'd', '6027', 'j', 'e', 'c', 't', '9983', '5471', '2649', 't', '2631', 'r', 'h', '293', 'j', '8699', 'p', 'k', '5433']

SOLUTION: c, d, e, h, j, k, p, r, t

PROBLEM: ['5785', '5779', 't', '9031', 'u', 't', 'y', 'v', '7895', '1195', 'm', '3591', 'm', '5029', '3825', 'e', 'o']

SOLUTION:
e, m, o, t, u, v, y