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:
['j', '917', 'w', 't', '8873', '1431', '8059', '7041']

Ex Output:
j, t, w


Ex Input:
['d', 'g', '9019', '9987', '8713', '9513', 'a', '2043', 'd', '5817', 'w', 'd']

Ex Output:
a, d, g, w


Ex Input:
['n', 'z', 'k', 'y', '5521', 'm', '3937', 'v', 'n', 'l', '4125', 'a', '6175', 'b', '4063', '8871', '5465', 'n', '5567', '9835', '1721', '7643', '5599', '5109', 't', '647', '4545', '5251', 'p', '6721', '6145', 'w']

Ex Output:

a, b, k, l, m, n, p, t, v, w, y, z