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.

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

['y', 'g', '107', '4899', '6357', '9777', 'k', '1865', '7029', 'q', 'x', '7051', 's', '6125', '4285', '2731', 'z', 'a', '737', '6137']
a, g, k, q, s, x, y, z

['c', '5113', '1313', '2669', 'n', '9625', 'z', '9605', '3543', '4603', 'j', '379', '97', 'w', 'v', 'x', 'k', 'n', '9199', '7799', '7483', '4257', '7543', '1591', 'l', 'h', 'v', 'q', '243', '9367', 'b', '187', 's']

b, c, h, j, k, l, n, q, s, v, w, x, z