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.

['z', 'l', '1759', 'k', '8197', 'v', '931', '2587', '7219', '3455', 'e', '8135', 'm', 'n', 'm']
e, k, l, m, n, v, z

['w', '5341', 'b', '6243', 'v', '877', '1087', '6763', '5241', '3369', '9119', 't', 'v', 'j', '8261', 'o', 'b']
b, j, o, t, v, w

['a', '9315', 'u', '2761', 'g', 'r', '6265', '8227', 'x', '1057', 'i', 's', '6957', 'i', 'u', '5603', 'c', '8909']

a, c, g, i, r, s, u, x