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: ['b', 'd', '8153', 'u', '3695', '5317']

Answer: b, d, u


Question: ['7839', '849', '5651', '4275', 'e', '5453', 'h', '2099', '485', 'i', 'm', 'n', '6563', '5675', '4001', 'h', 'm', 'z', '3467', '4237', '5035', '5609', '8475', '5171', 'v', '3883', '8461', '8611', '4853', 'd']

Answer: d, e, h, i, m, n, v, z


Question: ['r', '3393', 'b', 'o', 'p', '8769', 'y', 'p', 'q', '9327', '5253', 'p', '121', 'g', '7269', 'p', '2059', 'q', 'k', '1239', 'w', '5873', 'b', 'm', 'f', 'z', 'u', '633', 'd', 'p', '6433', 'z', 'l', 'v', 'r', 't', 'h', 'v', '8399', 'g', 'm']

Answer:
b, d, f, g, h, k, l, m, o, p, q, r, t, u, v, w, y, z