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: ['5075', '9169', '4659', '7605']

Output: -1


Input: Consider Input: ['t', 'h', '6141', 'g', 'f', 'z', 'n', 'b', 'k', '9059', 'y', 'p', '4289', '2683', 'a', '3267', 'w', 'p', 't', '3623', '7759', 'a', 'o', 'm', '9815', 'q', 'u', '8051', '6871']

Output: a, b, f, g, h, k, m, n, o, p, q, t, u, w, y, z


Input: Consider Input: ['a', '5797', 'u', 'a', '4339', 'h', '2013', '949', '2571', 'b', '4569', '5719']


Output: a, b, h, u