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.

['m', '7517', '9361', '9567', '8785', 'k', '5699', '3585', 'v', '1913', '1651', 'g', 'p', '2731', 'q', 'h', '467', 'r', '1091', '9801', 'a', '6645']
a, g, h, k, m, p, q, r, v

['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, d, f, g, k, l, m, n, p, q, s, v, w, z

['501', 'v', 'v', '3347', '6757', 'z', '7051', '61', '9553', 'r', '1733', '4243', '5965', 's', 'x', '8559', 'n', '2057', 'm', '3541', '1789', '7709', '8045', 'p', '7827', 'c', 'y', '5529', 'v', '8485', 'o', '2947', 'r']

c, m, n, o, p, r, s, v, x, y, z