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: ['815', '6967', '6553', 'r', 'y', '3641', 'q', 'b', '6131', '4289', 'w', '6093', '6055', 'i', 'b', 'y', '5107', 'v', 'g', '9709', 'x', 'i']

A: b, g, i, q, r, v, w, x, y
****
Q: ['4743', '9687', '2887', '4413', 'r', 'w', '2355', 'l', 'd', '453', 'o', 'm', '4351', '5881', '3963', 'g', 'r', 'z', 'q', '7555', 'y', '9555', '405', 'n', 'l', '6733', '1763', 'v', '9925', 'y', '633', '827', 'w']

A: d, g, l, m, n, o, q, r, v, w, y, z
****
Q: ['8321', '649', '3019', 'n', 'z', 'g', '8947', 'f', 'm', 'g', '7325', 'h', '185', '185', 'y', 'z', 'g', '6441', 'c', 'r', '5635', '2801', 'o']

A:
c, f, g, h, m, n, o, r, y, z
****