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:
['1979', 'b', 't', '1101', '7953', '2451', '7539', '6833', 'u', '49']

Ex Output:
b, t, u


Ex Input:
['j', 'f', '9567', 'f', '7383', 'k', '599', '1091', '1501', 'y', 'o', 'c']

Ex Output:
c, f, j, k, o, y


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