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: ['s', 'u']

A: s, u
****
Q: ['r', 's', '3409', 'a', 'e', '6855', 'i', 'n', '8655', 's', 't', '8401', 'u', '9603', '8815', 'q', 'a', 'x', 'i', '8455', 'e', '5877', '3917', 'p']

A: a, e, i, n, p, q, r, s, t, u, x
****
Q: ['1661', '7201', '2185', 't', 's', 'm', '2563', 'j', 'v', '2271', '8409', '6571', '311', '8377', '7785', 'o', 'u', '9287', '9817', '8097', '1273', '1229', 'i', 'a', '3279', '3359']

A:
a, i, j, m, o, s, t, u, v
****