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.

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

A: l, m, n, p, u, w, x, y
****
Q: ['9351', 'v', 'h', 'z', 'g', 'f', 't', 'q', 'g', 'o', '4073', 'n', '6149', '1735', '157', 'm']

A: f, g, h, m, n, o, q, t, v, z
****
Q: ['t', '4705', '6525', '8581', '3405', 'r', 'n', '6023', '5001', 'r', '8909', '4671', 'z', '4117', 'e', 'u', 'f', '4417', '8977', '3743', '107', 'm', 'e', '5053', 'r', '3035', 'f', '1489', '8517', 'w', '6319', 'n']

A:
e, f, m, n, r, t, u, w, z
****