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.

Example Input: ['o', '9599']
Example Output: o

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

Example Input: ['7975', 'm', '1279', 'n', 'y', 'b', 'd', 'z', '871', '799', 'j']
Example Output:
b, d, j, m, n, y, z