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:
['1983', '1835', '6543', '6399', '4177', '9385', '7127', 'p', 'l', 'u', 'g', 't', '3423', 'g', 'b', 'l', '3133', '2429']

Ex Output:
b, g, l, p, t, u


Ex Input:
['305', '95', 'e', 'q', 'e', '341', 'u', 'w', '5911', '6851', 's', 'u', '2355', 'd', '4151', 'w', '4421', '1129', '8065', 'k', 'q', '3649']

Ex Output:
d, e, k, q, s, u, w


Ex Input:
['5193', 'i', 'q', 'z', '5301', '3849', '3585', '8767', 'o', '8743', '5185', '6075', '4431', '7409', 'b', '2873', 'j', 'g', '1061', '2989', 't', 'v', '4975', 'u', '771', '6307', '7297', '5021', '7653', 'i', '9535', '1591', '3683', '609', 'u', 'f']

Ex Output:

b, f, g, i, j, o, q, t, u, v, z