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]: ['r', 's', '3409', 'a', 'e', '6855', 'i', 'n', '8655', 's', 't', '8401', 'u', '9603', '8815', 'q', 'a', 'x', 'i', '8455', 'e', '5877', '3917', 'p']
[A]: a, e, i, n, p, q, r, s, t, u, x


[Q]: ['x', 'b', '1467', 'y', '2101', 'y', 'm', '2745', 'z', '429', '7523', 'e', 'f']
[A]: b, e, f, m, x, y, z


[Q]: ['7349', 'c', '3447', 'c', 'k', 'i', '7601', '8019', 'j', 'v', '6055', 'r', 'f', 'q', 's', '4721', 'v', 'w', '8525', '5945', 's', 'q', 'w', 'z', 'b', '2203', 'a', 'i', 'a', '989', 'a', '9593', '4097', '9419', '9419', 'p', 'b', '7697']
[A]:
a, b, c, f, i, j, k, p, q, r, s, v, w, z