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

Output: l


Input: Consider Input: ['1657', 'u', '1849', '425', 'v', '6435', 'j', '2985', '921', '9553', '2621', 'i', '7103', 'd', '8563', 'l', 'b', '6727', '4235', 'n', '8021', 'd', 'z', '437', 'm', '5695', 't', '3421', 'e', 'a', '2941', '791', '1417', '9247', 'h']

Output: a, b, d, e, h, i, j, l, m, n, t, u, v, z


Input: Consider Input: ['1537', '7657', 't', '2783', '3321', 'g', '2081', '1449', '8549', '9633', 'l', 'm', 'w', 'z', '7531', '1625', 'e', 'q', 'g', '7051', '3609', 'r', 't', 'f', 'l', '7295', '9715', '2987', 'b', '9967', 'n', 'x', 'x', '4855', 't', 's', 'm', 'g', 'v', 'r', '2219', '551', '5115']


Output: b, e, f, g, l, m, n, q, r, s, t, v, w, x, z