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.

Ex Input:
['6697', 'j', '1571', '4989', 'o', '1143', 'i', '2969', '2541', '4899', 'i', '4751', 'n', 'b', '801', '4357', '3855', '49', 'm', '211', '7281', '121', '5231', '8313', '8967', '8043', '7699', 'r', '4315', '8637', '3339', '4437']

Ex Output:
b, i, j, m, n, o, r

Ex Input:
['i', '4447', 'g', 'o', 'j', 'p', 'l', 'q', 'o', '8777', 'r', 'v', '961', '6083']

Ex Output:
g, i, j, l, o, p, q, r, v

Ex Input:
['2781', '7229', 'm', 'z', '2867', 'n', '5613', 'c', '6897', 'b', '771', '905', '3497', 'p', '6031', 'o', 'u', 'q', 'f', '577', '5699', '7211', '9377', '8327', '6251', '5953', '8257', 'c', '3117', 'j', 'i', 'v', '1861', '2217', '1509', 'z', '2807', 't', '123', 'j', '8473']

Ex Output:
b, c, f, i, j, m, n, o, p, q, t, u, v, z