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: ['1983', '1835', '6543', '6399', '4177', '9385', '7127', 'p', 'l', 'u', 'g', 't', '3423', 'g', 'b', 'l', '3133', '2429']

A: b, g, l, p, t, u
****
Q: ['u', '8229', '2731', '6595', '4675', 'n', 'a', '7361', '7401', '7273', 'b', '279', '5539', '7919', 'j', 'x', '9521', '8837', '7391', 'h', 'x', 'h', '7283', 't', '3769', '2317', '9131', 'h', 'y', 'c', '1625', 'm', 'e', 'a', '8437', '7543', 'p', '2451', 'k', 'r']

A: a, b, c, e, h, j, k, m, n, p, r, t, u, x, y
****
Q: ['3749', '5907', '2437', '7141', '1035', '4809', 'h', 'b', '5065', 't', 'a', 'c', '827', '4609', '815', '9473', '4171', '7519', '7439', '213', 'e', 'r', 'j']

A:
a, b, c, e, h, j, r, t
****