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:
['2047', '4403', 'g', '3017', '1627', 'v', 'r', '2237', '5513', 'o', 'v', '7229', '9801', 'j', '443', 'z', 'q', 'y', '7447', '1659', '3411', '55', '5153', '9921', '2195', '1075', '8187', 'p', 'x', 'h', 'y', 't', 'a', 'r', 'f']
answer:
a, f, g, h, j, o, p, q, r, t, v, x, y, z


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


question:
['2523', '6183', '1769', '799', 'z', 'j', 'l', 't', '9373', '2557', '7287', 'p', '2937', 'u', 'b', 'b', '8755', 'p', 's', 'g', '2733', 'v', '6139', 'r', '6127', '2107', 'q', '8435', '2803', 'w', '2587', 'i', '2627', '5935', 'h', '3847', '9537', '3077', 'o', 'v', '4611', 't', '1669', '5679', 'd']
answer:

b, d, g, h, i, j, l, o, p, q, r, s, t, u, v, w, z