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: ['l', 'u', '3901', '341', '5801']

Output: l, u


Input: Consider Input: ['163', 'x', 'g', '5997', 'm', 'l', '7225', '7907', '375', 'y', 'a', 'j', 'c', 'j', '7755', '147', 'h', '3845', 'y', 's', 'h', 'u', '8737', '6091', 'j', 'f', 'c', '7395', '881', '1771', 'y', '3691', 'h']

Output: a, c, f, g, h, j, l, m, s, u, x, y


Input: Consider Input: ['339', 'd', '3943', '287', 'n', '7917', 'z', '749', 'o', '9483', '3581', 'k', 'j', '9563', 'j', '2311', 'x', 'z']


Output: d, j, k, n, o, x, z