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.
Input: ['4525', 'v', '1705', '3449', 'z', 'g', 'r', 'h', 'd', '1489', '1123', 'z', 'r', 'p', '3883', 'r', 'v', '1555', '8761', '4843', '7335', 'q', 'b', 'o', '2975', '9707', 'b', 'i', '2683', '7341', 'k', '9271', 'e', '6303', '9357', '7661', 't']
Output:
b, d, e, g, h, i, k, o, p, q, r, t, v, z