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]: ['8815', 'w', '8629', 'y', '3891']
[EX A]: w, y

[EX Q]: ['1367', 'h', '4153', '1587', 'h', 'b', 'n', 'u', 'n']
[EX A]: b, h, n, u

[EX Q]: ['4123', '1397', '103', 'w', 't', 'j', '233', '7239', 'b', 'n', 't', '6273', 'l', '1167', '8389', '5609', '9029', '7741', 'o', 'p', '6547', '5593', 'd', '8401', 's', '4243', 's', 'u', 'm', '6659', '5691', '2105', '8897']
[EX A]:
b, d, j, l, m, n, o, p, s, t, u, w