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]: ['k', 'n']
[EX A]: k, n

[EX Q]: ['8451', 'x', '9965', '9303', 'm', 'f', '4205', 'y', 'n', '8521', '9995', 'z', 's', '3519', 'k', 'e', 'o', 'k', '9611', 'q', 'l', 'p', '3339', '4023', 'n', 'd', '8903', 'a', 'k', 'u', '4009', 'e', 'm', '989', '4495']
[EX A]: a, d, e, f, k, l, m, n, o, p, q, s, u, x, y, z

[EX Q]: ['f', 'r', 'k', '235', '4077', '2365', '6179', '3029', '2831', '7801', '5575', '6221', 'z', 'a', '425', '6919', '3879', '9601', '9401', 'w', '9647']
[EX A]:
a, f, k, r, w, z