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: ['x', 'e', 'c', 'i', '8931', '3243', '2541', '4091', 'j', '3951', 'i', '1767', 'o', '6763', 'a', 'f', '7221', 'k', 'q', '8633', '2339', '5037', 'u', 'j', 't', '3241', 'z', '7431', 'i', 'i', '9481', '9935', 's', '6649', 'a', 'v', 'n']
Solution:
a, c, e, f, i, j, k, n, o, q, s, t, u, v, x, z