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.

Q: ['u', 'k', 'd', '4393', 'u', 'h', 'q', '833', 'k', 'l', '5749', 'r', '7123', '1003', 'z', '531', 'o', 'u', '6601', '6975', '4905', 'n', 'e']

A: d, e, h, k, l, n, o, q, r, u, z
****
Q: ['2697', 's', '8733', 'n', '5871', 'f']

A: f, n, s
****
Q: ['u', '7263', 't', '8645', '2795', 'r', '9683', '1827', '7785', 'x', 'n', 'h', '8171', 'q', '6205', 'f', 'f', '1137', 'w', 'r', '4827', 'j', '2085', '1333', 'g', '2873', '2973', 't', 'm', '2007', 'u', '7501', 'k', 'd', '4623', 'v', '4955', 'v', '37', '4805', 'e', 'p', 't']

A:
d, e, f, g, h, j, k, m, n, p, q, r, t, u, v, w, x
****