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:
['t', 'a', '2481', '2841', 'a', '2871', 'm', '4435', 'g', '8201', '4351', '9045', 'o']

Ex Output:
a, g, m, o, t


Ex Input:
['9403', '9881', '8391', 't', '1793', 'w', 'x', 'y', '6383', 'j', 'r', '5323', 'r', 'l', 'e', 'u', '7193', '2309', '837', 'z', 'w', 'n', '4427', '8269', '6333', 'a', 'p', '1933', '8497', '2665', '1349', '6807', '9009', 'b']

Ex Output:
a, b, e, j, l, n, p, r, t, u, w, x, y, z


Ex Input:
['8205', '1899', '5501', 'z', '1719']

Ex Output:

z