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]: ['7591', '7521', 'm', '1429', 'x']
[EX A]: m, x

[EX Q]: ['l', '1213', 'm', 'k', '7825', '3501', '2397', '2313', 'v', '4119', 'h', 't', '6137', 'l', '9851', 'q', '9661', 'b', 'z', '1437', '1759', 'l', '611', '5085', '4443', 'n', 'u', 'b', '2511', '6023', '7157', 'n', '9921', 'o', 'a', 'o', 'w', 't', 'o', '1607', '6751', 'n', 'b']
[EX A]: a, b, h, k, l, m, n, o, q, t, u, v, w, z

[EX Q]: ['2937', 'w', 'w', '1961', '1395', '8289', 'o', 'i', '3523', 'k', 'g', 'p', '8001', 'l', 'm', '4269', '9859', '3247', 'u', '1391', 'r', 'm', 't', '6865', '7741', 'r', 'a', 'u', '4249', '7569', 's', '1273', 'm', 'y', 'u', 'j', '1627', '8637', 'l', '7529', 't', '2919', '7315', 'r']
[EX A]:
a, g, i, j, k, l, m, o, p, r, s, t, u, w, y