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: ['749', 'r', 'a', 's', 't', '5905', 'm', 'd', '8437', '4583']

A: a, d, m, r, s, t
****
Q: ['h', '1797', '8211', 'n', 'r', '7707', '2063', '4655', 'x', '5521', '8327', 'g', '7659', 'i', 'x', 'w', '9465', '4625', 'q', '5377', 'r', '225', 'r', 'i', 'e', '4163', 'g', 'g', '3537', 's']

A: e, g, h, i, n, q, r, s, w, x
****
Q: ['p', '4859', '8831', 'g', 'k', 'c', '4255', 's', '3053', '2927', 'z', '8169', '7949', '9935', 'j', '7467', 'j', 's', 'j', 't', '345', '5309', '3811', 'm', '3609', '1245', '2037', 'p', 'u', 'h', 'd', 'b', 's', '8069', '8971', '5819', 'v', 'i', 'y', '5093', 'q', 'f']

A:
b, c, d, f, g, h, i, j, k, m, p, q, s, t, u, v, y, z
****