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:
['1707', '381', '3957', '7853', '4987']

Ex Output:
-1


Ex Input:
['4637', 'f', '2639', '8623', 'w', 'e', 'k', '5503', 'x', '6633', '7553', '1455', 'u', '1773', 'r', 'u', '1489', 'u', '1303', '9683', 'z', '565', '7041', 'x', 'z', '9431', 'k', 'v', 'j', 'z', '5469', '5665', '4089', '4951', '8263', '5675', '4095', '7745', 'z', '2437', 'd', 'e', 'w']

Ex Output:
d, e, f, j, k, r, u, v, w, x, z


Ex Input:
['r', '3533', 'g', 'f', '6573', 'g', 'u', 'p', 'a', '7425', 'm', 'f', '7689', '7375', 'j']

Ex Output:

a, f, g, j, m, p, r, u