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.

['w', 'g', '1649', 'a', '2115', '6763', 'r', 't', 'l', 's', 'y', '5659', 'a', 'b']
a, b, g, l, r, s, t, w, y

['1627', 'r', '2429', 'b', '4451', 's', 'k', 'm', '269', 'l', '709', 's', 'q', '985', 'x', 'j', 'k', 'k', '6603', 'v', '9497', '477', '5803', 'c', 't', 'f', '3189', '6419', '8561', '5709', 'u', 'z', '5717', '9711', 'w', 'y', 'm', 'v']
b, c, f, j, k, l, m, q, r, s, t, u, v, w, x, y, z

['7487', '4479', 'n', '8055', 'a', '3929', 'v', 'f', 'b', '2335', 'q', '3453', '1413', '3253', '8267', '509', 'q', 'o', 'o', 'a', 'x', '4407', '1775', '1203', '2695', '2775', 'e', 'y', '349']

a, b, e, f, n, o, q, v, x, y