Instructions: 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: ['849', '2665', '481', 'r', 'b', 's', '8733', '1325', '3699', '4335', 'b', 'd', 'z', 'v', 'e', 'd', '6371', 'z', 'v', 'f', '5995', '6813', '1023', 't', '9153', '5927', 'h', '5593', 'l', 's', '9875', '501', '1177', '8183', 'f', 'p']
Output:
b, d, e, f, h, l, p, r, s, t, v, z