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.

[Q]: ['2915', '6033', '5541', '4685', '1263', '6701', 's', '7269', 'g', '8033', '8171', '6917', 'l', '2913', '447', 'g', 'a', 'z', 'o', '7563', '5385', '5259', '5067', '4869', '2653', '6925', '7001', '8553', 'x', '1243', '9131', '5037']
[A]: a, g, l, o, s, x, z


[Q]: ['8235', 't', '1695', '9899', '3633', 't', '1823', 'r', 'x']
[A]: r, t, x


[Q]: ['l', '3623', '1083', '5367', 'k']
[A]:
k, l