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: ['8495', 'p', 'j', 'm', 'n', '9115', '1183', 'r', 'r', '8735', 'a', 'i', 'k', 'p', '8927', 'r', '9283', '9563', 'g', '2503', 'h', '1091', '5257', 'a', '3061', '2835', 'l', 'w', 'j', '7617', '8793', '7463', 'h', '8467', '7337', 'b', '4655', 'd']

SOLUTION: a, b, d, g, h, i, j, k, l, m, n, p, r, w

PROBLEM: ['2995', '8179', '8131', '5655', 'j', 'q', 'l', '3193', '1823', 'y', 'n', '7645', 's', '5665', 'r']

SOLUTION: j, l, n, q, r, s, y

PROBLEM: ['4435', 'j', 'd', '2463', '2407', 'j', 'c', '7399', 'p', 'v', '4063', '7665', 's', '4767', 'm', '6151', '431', '1647', '95', 's', 'n', '5943', '4777']

SOLUTION:
c, d, j, m, n, p, s, v