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.

['m', '7807', 'n', 'w', '5097', '1023', '2723', 'u', '3055', '7285', 'f', 'm', 'w', '5197', '9743', '7519', '4451', 'c', 't', '1939', '5847']
c, f, m, n, t, u, w

['g', 'x', 'l', 'e', 'd', '1345', '1763', 'm', 'c', '2057', 's', 'a', '4127', 'y', 'h', '8581', 'o', '9203', '4761', 'd', 'u', 'n']
a, c, d, e, g, h, l, m, n, o, s, u, x, y

['1077', '8849', 'k', '7169', 'f', 'f', 'j', 'l', 'j', 'r', '3823', '3259', '4851', '425', 'r', '7763', 'v', 'l', '3955', 'a', '9783', 't', 'i', 'w', '5769', '7939', '2677', 'd', 'l', 's', 'c', 'z']

a, c, d, f, i, j, k, l, r, s, t, v, w, z