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.

['g', 'x', 'l', 'e', 'd', '1345', '1763', 'm', 'c', '2057', 's', 'a', '4127', 'y', 'h', '8581', 'o', '9203', '4761', 'd', 'u', 'n']
a, c, d, e, g, h, l, m, n, o, s, u, x, y

['c', '7039', 'g', '1899', 'r', '507', 'c', '2587', '3865', '1729', '3927', 'r', '3535', '2791', 'm', 'l', 'r']
c, g, l, m, r

['v', 'c', '1375', 'd', 'h', '2023', 'b', '2469', '225', '7731', '757', 'c', 'm', '7543', 'u', '9541', 'w', '5701', '9121', '3505', '909', 'f', '617']

b, c, d, f, h, m, u, v, w