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', '6537', '4063', '6413', 'k', 'd', '2479', 'p', '2251', 'q', '7079', 'r', 'd', 'p', '3347', '1391', '9847', '4487', 'u', '6951', '5285', '5837', '6747', 'r', 's', 'c', 'x', 'b', 'q', 'y', 'd', '331', '679', 'v', '1919', 'f', 'p', '1267', '3151']
b, c, d, f, k, m, p, q, r, s, u, v, x, y

['6955', '721', '2763', '8121', '9109', '6341', 'p', 't', 'x', '6963', '1137', 'z', 'u', '1949', '7029', 't', '9539', 'a', 'u', '1873']
a, p, t, u, x, z

['v', 'm', '3029', '5767', '3329', 'k', '3985', '6551', '9361', '4071', '571', '329', '4023', '9961', '5507', '6945', 'k', 'b', '3551', '5409', 'd']

b, d, k, m, v