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: ['t', 't', 'p', '3245', 'x', 'g', 'i', 'u', '2599', '8613', 't', 'v', 'p', '5635', 'y', '9567', '5193', '8617', 'q', 'f']

SOLUTION: f, g, i, p, q, t, u, v, x, y

PROBLEM: ['w', 'a', 'm', 'd', '409', 'm', 'v', 's', '7801', 'l', '8551', 'k', '867', 'n', '7731', 'z', '3773', '9137', 'v', 's', 'p', 'p', 'f', 'z', 'g', 'q', 'g', '877', '697', '2057', '8389', '2399', '5263', '2761', '9841', '1781', 'l', '8023']

SOLUTION: a, d, f, g, k, l, m, n, p, q, s, v, w, z

PROBLEM: ['s', 'i', 'n']

SOLUTION:
i, n, s