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: ['k', 'r', 'f', '4369', 'z', 'z', 'l', '143', 'r', '707', '9167', 'g', '1749', 'i']

Answer: f, g, i, k, l, r, z


Question: ['6655', '7445', '1795', '7495', 'h', 'z', 'u', '2199', 'r', 'p', '2245']

Answer: h, p, r, u, z


Question: ['1821', '9451', '2139', 'd', '8751', '5335', 'p', '9175', '4339', '4569', '2499', '4871', 'j', '4465', 'r', 'f', '8041', '4919', 'm', 'e', '4789', 'l', 't', 'i', 'm', '8261', 'g']

Answer:
d, e, f, g, i, j, l, m, p, r, t