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: ['5553', 'f', '3881', '8867', 's', 'd', 'a', '375', '7889', '3949', '2905', 'w', 'q', 'q', 'd', '4203', 'i', '2601', 'y', 'p', 'k']

A: a, d, f, i, k, p, q, s, w, y
****
Q: ['1983', '1835', '6543', '6399', '4177', '9385', '7127', 'p', 'l', 'u', 'g', 't', '3423', 'g', 'b', 'l', '3133', '2429']

A: b, g, l, p, t, u
****
Q: ['2791', '6965', '4715', 'h', 'r', '2561', '8875', 'e', '509', '6179', '8501', 'n', '4485', '8521', 'h']

A:
e, h, n, r
****