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: ['2293', 'p', '9787', '7241', '8689', 'u', '3141', 'h', 'c', 'b', 'f', 's', '319', 'c', 'p', '6909', 'p', 'f', '1717', 'd', '2285', 's']

A: b, c, d, f, h, p, s, u
****
Q: ['2349', 'p', 'a', '435', 'y', 'h', '3249', 'o']

A: a, h, o, p, y
****
Q: ['9751', '4497', '1631', 'n', 'a', '3567', 'z', '2059', 'k', 'x', '2613', '1393', 'j', '9985', '4089']

A:
a, j, k, n, x, z
****