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:
['p', 'g', 'q', 'e', '8045', '9999', '9555', '7995', '7195', 'z', 't', '5223', '3699', 'i', '4797', '3817', 'x', 'y', 'w', 'o', '8915', '7803', 'n', '1117', 'c', '9647', 'p', 'e', '9669', '4845', '9255', '4545', '3693', '6871', 'w', '4327', '3285', 'k', 'f', 'x', 'i', 'b', '5967', '6601']

Ex Output:
b, c, e, f, g, i, k, n, o, p, q, t, w, x, y, z


Ex Input:
['o', '1099', 'r', '8995', 'o', '2909']

Ex Output:
o, r


Ex Input:
['u', '9249', 'u', 't', 'm', 'm', 'n', 'w', '8617', '2729', 'i', 'l', '2971', '3227', 'b', '9017', '4711', 'i', 't', 'r', 'a', 'a', '1701', '6397', '4535', '9167', '6039', '6111', '849', 'p', '8197', '2645', '5147', 'u', 'l', '7419', 'w', 'w', 'k', 'x', 'c', '3377', '4015', '1297', 'f']

Ex Output:

a, b, c, f, i, k, l, m, n, p, r, t, u, w, x