instruction:
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.
question:
['8357', 'x', 'w', '287', 'z', '2733', '1757', 'w', 'g', '1393', '7201', '4931', 'k', '5185', 'x', '6313', '2255', 'z', 'v', '3593', '6191', '4423', 'm', 'k', '3209', '3559', 'c', 'n', 'm', '5461', '2997', '235', '4045', '6597', 'v', 'e', 'p', 'c', 'k', 'd', '5529', '6241', 'u', 'f', '8067']
answer:
c, d, e, f, g, k, m, n, p, u, v, w, x, z


question:
['m', '3809', 'l', 'k', '1929', '7963', 'n', 'u', '2125', 'g', 'o', '8325', 'o', 'h', 'y', '3025', 'e', 'e', 'c', 'x', '8445', '4979', 'z', 'f', '4201', '4765', 'g']
answer:
c, e, f, g, h, k, l, m, n, o, u, x, y, z


question:
['w', '5163', 'x', 'e', '3093', '6341', '8505', '1579', '297', 'j', '9313', 'c', '7413', 's', '4515', 's', 'r', 'b', '8137', '7375', '7189', 'i', 'y', 'm', '4083', 'y', '4209', '49', '5723', '5589', 'r', '319', 'e', 'l', 'h', 'p', '5351', 'u', 'j', '229', 'f', 'd']
answer:

b, c, d, e, f, h, i, j, l, m, p, r, s, u, w, x, y