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:
['p', '3981', 'e', '5949', 'p', '4075', '1919', 'w', 'r', '8059', '4303', 'f', '5201', '2255', '2737', '7395', '8809', 'j', 'z', 'n', '4797']
answer:
e, f, j, n, p, r, w, z


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:
['3621', '9347', '4195', 'g', 'w', 'i', 't', 's', 'x', '945', '4203', '4823', 'b']
answer:

b, g, i, s, t, w, x