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.

['1983', '1835', '6543', '6399', '4177', '9385', '7127', 'p', 'l', 'u', 'g', 't', '3423', 'g', 'b', 'l', '3133', '2429']
b, g, l, p, t, u

['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

['j', 'b', '6847', 'g', 'f', 'l', 'g', 's', '8267', '3741', '465', '7159', '2043', 'k', '5353', 'e', '1233', 'o', 'c', '7817', 't', '5627', 'o', 'm', 'b', 'c', '5161', '4103', 'y', '7139', '557', 'h', 'q']

b, c, e, f, g, h, j, k, l, m, o, q, s, t, y