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:
['d', 'm', 'k', '3513', '8241', '5541', 'm', 's', '1993', '6163', '2753', 'd', 'b', 'm', 'i', '7647', '8631', '9119', '2165', 'x', '3911', '2769', '1673', '7195', 't', 'w', '5555', 'o', '3265']
answer:
b, d, i, k, m, o, s, t, w, x


question:
['3035', 'f', 'k', 'e', '3023', 'p', '9667', '5277', '4757', '8433', 'g', '1399', '7721', 'n', 'p', '7469', '7581', '5679', 'g', 'q']
answer:
e, f, g, k, n, p, q


question:
['i', 'l', 'j', '7421', '2921', 'z', 'g', 'r', 'c', '3603', 'p', '9851', 'b', '5335', '4825', '729', '7411', 'n', '8251', '5559', 'o', 'i', '4873', '2291', 'x', '2159', '5609', '1633', '1545', '1017', 'c', 'l', '7037', '2761', 'h', 'u', '9431', '7437', '781', 'f', '9631', '6931', 'f', '8469', 'e']
answer:

b, c, e, f, g, h, i, j, l, n, o, p, r, u, x, z