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]: ['4787', 'c', '1727', '9863', '8147', '3931', 'b', '1133', '3023', '7427', '7837', 'n', '7921', 'o', 'c', '3973', '1949', 'x', 'g', 'b', 'd', '8559', '8661', '4465', 'z', '369', 'q', 'e', 'y', '8629', '7665', 'i', 'r', 'n', 'z', '9115', '1393', '4899']
[A]: b, c, d, e, g, i, n, o, q, r, x, y, z


[Q]: ['x', 'j', '9747', 'i', '2015', '3505', 'q', 'n', 'h', '3011', 'u', '8043', 'j', 'f', 'd', 'a', 'p', '5817', 'l', 'q', '2275', 'n', '7085', '5373', 'l', 'g', 'b', '8043', '3085']
[A]: a, b, d, f, g, h, i, j, l, n, p, q, u, x


[Q]: ['4795', '4329', 'a', '7225', '6075', '9793', 'x', '9817', '9953', 'n', 't', '1423', '817', '1967', '7691', 'h', '4921', '6985', '1275', 'q', 'f', 'y']
[A]:
a, f, h, n, q, t, x, y