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: ['2247', 'w', 'h', '4675', '6153', 'f', '6029', 'o', 'd', 'j', 'z', 'y', 'i', '6899', '3917', 'u', '6447', '6405', 'a', '1705', '8585', 'v', 'f', 'r']

A: a, d, f, h, i, j, o, r, u, v, w, y, z
****
Q: ['6143', 'y', '5505', '9813', 'r', 'v', 'u', '8681', '2387', 'u', 'o', 'm', '9793', 'm']

A: m, o, r, u, v, y
****
Q: ['l', '7269', 'k', '85', 'i', '1245', '2307', 'l', 't', 'b', 'f', '3143', 'p', '6507', '517', 'n', '3827', 'b', '7541', 'l', '3667', 'c']

A:
b, c, f, i, k, l, n, p, t
****