Detailed Instructions: 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: ['r', 'b', '3773', '2773', 'q', 'k', 'i', 'f', '7267', 'a', 'u', 'h', '1469', 's', '9319', 't', 'e', 'e', '13', '7697', 'g', 'a', 'e', 'w', '6779', '9517', 'z', 's', 't', 'j', 'u', 'p', 'm', 'b', 'h', '3189']
A:
a, b, e, f, g, h, i, j, k, m, p, q, r, s, t, u, w, z