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: Consider Input: ['3127', '9253', '5667', '9453']

Output: -1


Input: Consider Input: ['8821', '9833', 'l']

Output: l


Input: Consider Input: ['p', 'p', '7527', '5277', '4631', 'c', '6291', '2083', 'w', 'q', '3929', '5593', '8057', 'a', 'z', 'x', '3343', 'e', 'b', 'f', 'e', '8775', '8791', 'y', 'b', '2505', 'j', 'd', '9699', '2651']


Output: a, b, c, d, e, f, j, p, q, w, x, y, z