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]: ['2329', 'i']
[EX A]: i

[EX Q]: ['9483', '501', 'j', 'k', '3103']
[EX A]: j, k

[EX Q]: ['f', 'b', '8167', 'z', 'r', 'v', '7699', '7269', 'f', '2913', '1021', '1637', '4195', '9015', 'l', '3741', 'w', '6447', 'r', '5667', 'c', '5555', '4711', 'f', '7541', '8299']
[EX A]:
b, c, f, l, r, v, w, z