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: ['z', 'l', '1759', 'k', '8197', 'v', '931', '2587', '7219', '3455', 'e', '8135', 'm', 'n', 'm']

SOLUTION: e, k, l, m, n, v, z

PROBLEM: ['w', '5341', 'b', '6243', 'v', '877', '1087', '6763', '5241', '3369', '9119', 't', 'v', 'j', '8261', 'o', 'b']

SOLUTION: b, j, o, t, v, w

PROBLEM: ['d', '3033', '5111', '9657', '899', '3717', '3231', '9849', '1065', '3493', '6111', '4435', '1565', '5363', '3463', 'j', '6885', '2331', '4683', 'c', '9419', '9727', 'z', '5985', '1957', '8585', '5299']

SOLUTION:
c, d, j, z