Given the task definition and input, reply with output. 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.

['4431', '7663', 'v', 'f', '5481', 'g', 'm', '327', '8619', '8699', 'd', '7713', 't', 'o', '619']

d, f, g, m, o, t, v