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:
['8741', 'h', '2147', '373', 'c', 'r', '2639', '3511', '1393', 't', '7173', 'f', '9371', '7659', 'q', '4799', 'f', '1967', '1905', '8783', 'i', 'n', 'z', '6395', 'u', 'i', '1493', '1395', '1909', '477', 'i', '8547', '393', '2203', '6893', 'y', '2085', '6445', '7753', '4027', 'h', 'y', '7963']
answer:
c, f, h, i, n, q, r, t, u, y, z


question:
['u', 'w', '401', 't', 'g', 'h', 'g', '8073', '9597', '1347', '7835', '5007', '977', 'p', '7679', 'b', '4883', '4931', '999', 'r', '1181', 'x', '2063', 'l', 'w', 'i', 'l', 'x', 'i', '9057', '5007', 'w', '743', '1635', 'y', 'f', '9227', 'z', '5227', 'd', '7129', 'k', '7657']
answer:
b, d, f, g, h, i, k, l, p, r, t, u, w, x, y, z


question:
['1573', 'x', '7085', '4703', '1639', 'f', 'o', 'g', '8299', '5597', '5423', '965', 'm', 'm', 'u', 'o', '7033', '701', 'g', '1421', 'w', 'v', 'y', '2445', 'j', 't', '875', 'b', '7491', 'c', 'd', 'j', '8103', '5127', 'd', 'h', '9185', 'x', '9257']
answer:

b, c, d, f, g, h, j, m, o, t, u, v, w, x, y