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: ['v', 'y', '7967', '6803', 'x', 'v', 's', 'e', '9649', '6931', '7897', 'n', '8639', 'q', '7525', '4465', 'd', '6985', 'o', '4921', '9427', 'h', '7351', 'u', '5609', 'l', 'b', '3695', '4151']
Output:
b, d, e, h, l, n, o, q, s, u, v, x, y