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.

['8235', 't', '1695', '9899', '3633', 't', '1823', 'r', 'x']
r, t, x

['u', 'k', 'd', '4393', 'u', 'h', 'q', '833', 'k', 'l', '5749', 'r', '7123', '1003', 'z', '531', 'o', 'u', '6601', '6975', '4905', 'n', 'e']
d, e, h, k, l, n, o, q, r, u, z

['m', 'b', 'c', '6565', 'x', '2215', '8671', '6321', 'm', '7921', '7201', '869', '5517', 'd', 'd', '1343', 'q', '1161', 'i', 't', 'a', '5265', 'x', '767', '6445', '7673', 's', '9547', '9841', 'b', '9287', '7681', 'g', '5375', 't', 'd', '4841', 'f', 'm', '6805']

a, b, c, d, f, g, i, m, q, s, t, x