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: ['8879', 'x', '1383', '4925', '2867', 'j', 't', 'e', 'w', 'p', 't', 'w', 'l', '7447', '1877', '7747', 'k', 'b', 'x', '8565', 'q', '8575', '5711', '2949', '5637', '2197', '4905']

A: b, e, j, k, l, p, q, t, w, x
****
Q: ['6737', 'g', '9985', '5257', 'k', 't', '7863', 'y', '8319', 'l', 'o', '6505', '6531', 'z', '3055', '2943', '3625', 'h', '4867']

A: g, h, k, l, o, t, y, z
****
Q: ['4455', 'x', 't', 'x', '1837', 'c', '3579', 'o', 'j', 'u', 'f', '3723', '6673', 'a', '4069', 'q', '2719', '6673', '2747', '9261', '2781', 't', 'x', 'x']

A:
a, c, f, j, o, q, t, u, x
****