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: ['8235', 't', '1695', '9899', '3633', 't', '1823', 'r', 'x']

SOLUTION: r, t, x

PROBLEM: ['a', 'i', '7725', '2483', 'e', 'j', '5337', 'b', '6835', '8231', 'm', 'v', 'a', '1475', 'n', '5823', 's', 'm', '7313', '2841', '2585', '4673', 'u', '2083', 'z', 'd', 'p', '2117', 'i', '587', 'i', 'a', '2527', '7967', '6567', 'n', '6145', 'r', 'f']

SOLUTION: a, b, d, e, f, i, j, m, n, p, r, s, u, v, z

PROBLEM: ['413', 'v', 'g', 'd', 'p', '2263', '4925', '3655', '6903', 'j', '7753', '2503', '5043', 'l', 'o', '193', 'u', 'y', '7669', 'c', 'u', 'f', '1699', '8657', '5297', '6091', '2797', '6301', '3407', '1675', 'z', '7339', '2107', 'z', '8029', 'a']

SOLUTION:
a, c, d, f, g, j, l, o, p, u, v, y, z