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', 'h', '6141', 'g', 'f', 'z', 'n', 'b', 'k', '9059', 'y', 'p', '4289', '2683', 'a', '3267', 'w', 'p', 't', '3623', '7759', 'a', 'o', 'm', '9815', 'q', 'u', '8051', '6871']

Ex Output:
a, b, f, g, h, k, m, n, o, p, q, t, u, w, y, z


Ex Input:
['4641', '2881', 'c', '4827']

Ex Output:
c


Ex Input:
['m', 'y', '9655', '4507', 'h', '9887', '8559', 'n', 'm', '4649', 'a', 'z', 'j', '3597', '6845', 'o', '6651', '4021', 'y', '5701', 'a', 'p', '3821', '4119', '1913', '1309', 'k', '2765', '9843', '3757', '6865', '819', 't']

Ex Output:

a, h, j, k, m, n, o, p, t, y, z