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.

Input: Consider Input: ['3395', '7471', 'n', '9537', '1255', '1997', '3085', '4863', '9797', '4275', 'k', 'f', '8973', '3939', 'p', 'q', '4977', '6231', '8745']

Output: f, k, n, p, q


Input: Consider Input: ['a', 'w', 'm', 'g', 'c', '5475', '7391', 't', '1049', 'p', 'd', '1397', 'k', 'x', 'j', '2525', 'f', '741']

Output: a, c, d, f, g, j, k, m, p, t, w, x


Input: Consider Input: ['7139', '2131', 'p', 'i', 't', '9067', '8643', '6477', 'q', '6425', '1909', 'o', '5441', '5927', 'z', 'l', 'e', 'z', '5617', '7455', '3569', 'e', 'u', '8879', '8443', 'o', 'c', '4873', '4201', '1029', '3393', 's', '6135', '5985', 'd', '2301', '9853', '8755', '5845', '7179', 'a', 'o', 'b', '6969', 'b']


Output: a, b, c, d, e, i, l, o, p, q, s, t, u, z