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.

[EX Q]: ['1429', '7273']
[EX A]: -1

[EX Q]: ['587', '3903', 'z', 'l', 'k', '5693', 'x', '1695', 'c', '3185', 'g', '9491', '8185', '1285', '2533', '6825', '3187', '6039', 'e', '251', 'w', '7741', '9573']
[EX A]: c, e, g, k, l, w, x, z

[EX Q]: ['95', 'z', '8853', 'j', '1843', 'p', '7915', 't', 'u', '4409', 'i']
[EX A]:
i, j, p, t, u, z