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: ['w', 'n', '729', '2491', 'n', 'x', '915', '1869', 'z', '8491', '9947', '561', '829', 'n', 't', 'i']

Output: i, n, t, w, x, z


Input: Consider Input: ['m', '7807', 'n', 'w', '5097', '1023', '2723', 'u', '3055', '7285', 'f', 'm', 'w', '5197', '9743', '7519', '4451', 'c', 't', '1939', '5847']

Output: c, f, m, n, t, u, w


Input: Consider Input: ['v', 'o', '7315', 'g', 'o', '9985', '4265', '4265', '8221', 'l', '9153']


Output: g, l, o, v