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', '2519', '4799', '4715', '7165', 'r', 'r', 'l', 'n', '6925', '8935', '9795', '5489', 'v', 'u', '6527', '2241', 'u', 'c', 'w', '9755', 'w', '9823', 'g']
c, g, l, n, r, u, v, w, z

['9385', '4021', 'y', '9629', 'u', '7623', 'd', '5155', 'x', '2605', '8893', 'l', 'p', 'a', 'm', '6699', 'i', '4503', '6623', 'm', 'l', '6115', 'p', 'w', '9691', '811', '4769', '2659', 'x', 'c', '6513', '5499', 's', 'q', 'f', 'v', 'z', 'w', 'z', '1361']
a, c, d, f, i, l, m, p, q, s, u, v, w, x, y, z

['x', 's', 'y', '8909', 'u', '7695', 'i', 'i', 'i', '2729', '9123', 'm', 'p', '5397', '7025', 'g', '6439', '5451', 't', 'g', '1135', 'n', 'l', '3827', 'z', '7895', 'h', 'z', '9565', '7223', '5723', 'm', 'w', '3815', '8495', '1771', 'p', '3453', 'u', 'v', '1491', 'x', 'z', '4871', '9283']

g, h, i, l, m, n, p, s, t, u, v, w, x, y, z