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:
['6627', '8037', 'q', 'e', 'j', 'p', '9613', '9317', 'm', 'm', '5345', 'f', '8105', '5665', '4175', '4793', '3707', 'i', 'b', '6745', '747', '8329', '1481', 'b', '8949', 'n', '4803', '1359', '3533', 'f', '543', '3003', '6943']
answer:
b, e, f, i, j, m, n, p, q


question:
['y', '8115', 'f', '5333', 'f', '3437', 'b', 'e', '5719', 'm', 'w', '95', '4863', 'k', '4895', 'a', '8179', 'm', '7919', '1731', '229', 'r', '1847', '7559', '6669']
answer:
a, b, e, f, k, m, r, w, y


question:
['q', '9703', '1327', 'n', '8067', 'y', 'h', '6691', '9691', '2981', '5475', 'f', 'p', '2243', 'o', 'g', 'g', '7411', '8555', '6887', 't', 'h', 'f', 'w', 'p', 'x', '8013', '8089', '6203', '6947', '5459', 'e', 't']
answer:

e, f, g, h, n, o, p, q, t, w, x, y