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: ['l', 'i']

SOLUTION: i, l

PROBLEM: ['7065', 'q', 't', '3177', '9035', 'i', 'l', 'd', '8961', '1183', '6507', 'u', 'c', 't', '2467', '7659', 'e', '8963', 'j', 'g', 'p', '6779', '7115']

SOLUTION: c, d, e, g, i, j, l, p, q, t, u

PROBLEM: ['r', 'k', 'w', 'k', '5983', '3275', '6043', '3605', 'j', 'z', 'j', '2279', '5409', '933', '6341', 'e', 'k', '1705', 'c', 'b', '3367', '8153', '9041', '6271']

SOLUTION:
b, c, e, j, k, r, w, z