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: ['t', 's', '1971', '7165', 'c', '4593', '3729', '2793', '5665', '5815', '9655', 'u', 'q', 'r', '4023', 'v', 'z', 'r', 'z', '8751', 'e', 'k', '9817', 'f', 'i', 'x', 'j', '4971', 'q', 'h', '2303', '5747', '6289', 'n', 'x', 'r', '7957', '2069', 'w', '9431', 'l']
Solution:
c, e, f, h, i, j, k, l, n, q, r, s, t, u, v, w, x, z