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]: ['q', 'g', 's', 'g', 'z', '987', '777']
[A]: g, q, s, z


[Q]: ['w', 'a', 'm', 'd', '409', 'm', 'v', 's', '7801', 'l', '8551', 'k', '867', 'n', '7731', 'z', '3773', '9137', 'v', 's', 'p', 'p', 'f', 'z', 'g', 'q', 'g', '877', '697', '2057', '8389', '2399', '5263', '2761', '9841', '1781', 'l', '8023']
[A]: a, d, f, g, k, l, m, n, p, q, s, v, w, z


[Q]: ['3947', '4809', 'b', 'a', '4769', '4179', '535', '5965', 'f', 'j', '2265', 'w', '3103', 'u']
[A]:
a, b, f, j, u, w