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.

Example input: ['8129', 'a', '4245', 'y', 'm', 'a']
Example output: a, m, y
Example explanation: Here, the unique alphabets in the list are 'a', 'y', and 'm', hence their sorted order is 'a, m, y'.
Q: ['q', '5581', 'c', '5129', '9509', '3153', 'n', '3053', '7093', '5043', '9515', '8261', 'r', '2117', 'k', '9829', 's', '5709', 'a', 'j', 'z', '833', 'v', '6683', 'k', '5027', 'u', 'n', '8417', 'v', '6289', 'd', '2415', 'b', '9635', 'y', 'w']
A:
a, b, c, d, j, k, n, q, r, s, u, v, w, y, z