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: ['t', 'c', 'r', '4459', 'o', '1407', 'x', '1515', '331', 'm', '1535', 'p', 'u', 'g', '2513', 'o', '7827', '8149', 'd', 'z', 'q', '5655', 'x', '9997', '2809', 'g', 'h', '6309', 'a', 'j', '9773', '2115', 't', '9113', 'q', 'o', '427', 's', '3815', '5423', 's', 'n', 'i', 'o', '3643']

Answer: a, c, d, g, h, i, j, m, n, o, p, q, r, s, t, u, x, z


Question: ['v', '6635', '5395', '3263', '4391', 'h', '1521', 'f', '9861', '6125', '1673', '3679', '8681', '4967', 'f', 'a', 'c', 'k', 'n', '4155', 'e', 'm', 'i', '1699', 'r', 'f', 'u', 'r', '3451', 'v', '7239', 'o', '4359', 'l', 'a', '2925']

Answer: a, c, e, f, h, i, k, l, m, n, o, r, u, v


Question: ['755', '1489', '6945', 'n', 'h', '5783', '9285', 'z', 'l', '4789', 'b', 'l', 'c', '6441', '7319', '6601', 'u', '2713', 'k', 'q', 't', '3563', '8029', '1519', '211', 'h', '2419', '6735', '1725', 'a', 'z', 'v', 'f', 't', 'x', 'u', '7019', '7513', 'l', 'h', 'x', 'p', '6959', '3985']

Answer:
a, b, c, f, h, k, l, n, p, q, t, u, v, x, z