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: ['d', '1625']

SOLUTION: d

PROBLEM: ['4123', '1397', '103', 'w', 't', 'j', '233', '7239', 'b', 'n', 't', '6273', 'l', '1167', '8389', '5609', '9029', '7741', 'o', 'p', '6547', '5593', 'd', '8401', 's', '4243', 's', 'u', 'm', '6659', '5691', '2105', '8897']

SOLUTION: b, d, j, l, m, n, o, p, s, t, u, w

PROBLEM: ['8731', '7401', 'd', '9671', '6085', '4699', 'v', '9213', '6017', 'j', '2451', '2253', 'n', '9989', 'y', 'r', '1883', '4401', 'm', '8991', 't', '9471', '8011', '8597', 'v', '2971', 'o', 'b', '8897', '3113', 'y', '1791', 'm', 'a', '2915', '5129', '6755', 'a', '3505', '9255', 'j', 'a', '9763', 's']

SOLUTION:
a, b, d, j, m, n, o, r, s, t, v, y