Definition: 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: ['z', '195', '4691', '3267', '7223', '2459', '323', 't', '5009', 'n', 'a']

a, n, t, z