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.
--------
Question: ['4041', 'l', 'g', '9571', '9295', '1395', 'l', 'p', 'f', 'w', 'g', '1721', '2421', 'w', 'z', '2235', 'p', '7851']

Answer: f, g, l, p, w, z


Question: ['c', '1693', 'l', 'u', 'x', '3609', 'h', '4159']

Answer: c, h, l, u, x


Question: ['4077', 'z', '6553', '7957', '7467', 'w', '1357', '7885', '9749']

Answer:
w, z