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.
One example: ['8129', 'a', '4245', 'y', 'm', 'a']
Solution is here: a, m, y
Explanation: Here, the unique alphabets in the list are 'a', 'y', and 'm', hence their sorted order is 'a, m, y'.

Now, solve this: ['7129', 'v', 's', '5371', '1789', 't', 'i', '8287', '3931', '8905', '1363', 'e', 'r', 'l', '533', '7949', '7591', 'n', '4679', '8453', 'd', '4385', '2379', '6627', '5951', '4505', 'd', 'j', '473', '9391', 's', '4661', 'e', '4527', '4095', 'b', '871', 'y', 'a', 'k', 'h', '4307', '5977']
Solution:
a, b, d, e, h, i, j, k, l, n, r, s, t, v, y