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: ['1297', '8999', 'm', 'z', 't', 'x', 's', '8581', '4927', 'w', '5401', 'c', 'q', 'g', '3239', '527', 'y', '719', '7111', 'g', '4079', 'b', '1907', 'a', '1137', 'w', '741', 'k', 'c', 'j', '4783', 'b', 'o', 'i', 'x', 'l', '3663', 'u', '8121', '977', 'z', '6811', '6229']
Solution:
a, b, c, g, i, j, k, l, m, o, q, s, t, u, w, x, y, z