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:
['8739', 'v', 'm', '6277', 'l', 's', '109', '8057', '3835', 'd', 'u', 'f', 'w', 'd', 'p', '7705', '3643', '4455', 'u', 'p', 'u', '9407', 'g', 'w', '595', 'z', '6827', '6879', 'w', 'w', '6973', 'm', 'e', '1553', 'v', '3529', '8953', '3903', '5713', '8249', 'e', '1113', 'b', 't', 'r']

Ex Output:
b, d, e, f, g, l, m, p, r, s, t, u, v, w, z


Ex Input:
['a', 'a', 'b']

Ex Output:
a, b


Ex Input:
['6617', 'p', 'u', '9623', '2395', 'i', 't', 'l', 'c', 'g', 'w', 'z', 'o', '7949', 'k', '4045', 'j', '8653', '561', '3519', '3753']

Ex Output:

c, g, i, j, k, l, o, p, t, u, w, z