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.

Example Input: ['8821', '9833', 'l']
Example Output: l

Example Input: ['x', '4283', 'n', 'b', 'g', 'p', '8305', '7781', '5907', 's', '1305', 'w', '8623', 'o', 'c', 'u', '1839', '2869', '7537', 'y', '2395', '5309', 'e', '4059', 'l', '6647', 'p', '9717', 'y', 'y', '3769', '2527', '2981', '5255', '4063', 'j', '4843', 'j', '9355', 'z']
Example Output: b, c, e, g, j, l, n, o, p, s, u, w, x, y, z

Example Input: ['o', '5435', '8261', '2157', '9197', '4049', 'm', '4867', 'e', 'g']
Example Output:
e, g, m, o