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.
Input: ['7679', 'c', '6413', 'k', '2435', '1529', 'y', 'g', 'u', 'j', '4545', 'l', 'r', 'e', 'c', '5019', '6325', 'q', '4713', 'v', 'j', 'k', 'r', '7181', 'g', '7295', '4831', '213', 'y', '2881', 'm', '9801', 'z', 'p', 'p', 'g', 'n', 'p', '5261', 'n', '4729']
Output:
c, e, g, j, k, l, m, n, p, q, r, u, v, y, z