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:
['h', 'g', '4563', 'v', 'm', '107']

Ex Output:
g, h, m, v


Ex Input:
['1595', '2915', 'o', 't', 'c', 'h', '3969', '5407']

Ex Output:
c, h, o, t


Ex Input:
['4615', 'c', 'b', 'z', '3305', '8873', 'b', 'g', '8623']

Ex Output:

b, c, g, z