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.

Ex Input:
['3307', 'r', '2665', '3453', 'f', 'd', 'v', '3801', '3153', '3137', 'y', 'i', '9681', 'k', '9253', 'y', 'i', '8631', '2375', '5131', 'r', 'z', '8645', '595', 's', '6749', '2665', '709', '8203']

Ex Output:
d, f, i, k, r, s, v, y, z


Ex Input:
['m', '6761']

Ex Output:
m


Ex Input:
['v', '9987', '9463', 'm', 'n', '9821', '7797', 'b', 'u', '8997', 'k', '47', '2301', '1169', '7455', '6849', 'v', 'w']

Ex Output:

b, k, m, n, u, v, w