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:
['u', '4731', 'l', 'p', '1997', '601', 'n', 'l', 'p', '211', '7355', '6537', 'w', 'x', '1741', '8145', '3689', 'm', 'y', '6945']

Ex Output:
l, m, n, p, u, w, x, y


Ex Input:
['1447', 'q', '9529', '2971', 's', '7351', '6753', '3493', 'v', 'c', 'x', '3097', '9145', 'b', 'e', 'b', '2967', '6933', 'e', 's', 'v', 'f', 'z', 'r']

Ex Output:
b, c, e, f, q, r, s, v, x, z


Ex Input:
['607', 'y', '7443', '2529', 'v', 'k', '7755', 'i', '3661', 'm', '1369', '7393', '1395', '7687', '4695', '1381', 'p', 'a', '5239', '6481', '2831', '5801', '6413', '9349', '5369', '6447', 'g', 't', 'r', '8081', '9471']

Ex Output:

a, g, i, k, m, p, r, t, v, y