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.

['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

['f', 'j', '9195', '3155', '2855', '5333', '5263', '9279', '687', 'e', '3055', '7233', '13', 'j', 'p', 'i', '8327', 'm', 'h', '3977', 'h', '7997', 'a', 'h', '4661', 'x', '8237', 'a', '5009', 'o', 'p', 'z', '2293', 'q', 'p', '5469', 'k', 'q', 'b', 'n', '1967', '4991']
a, b, e, f, h, i, j, k, m, n, o, p, q, x, z

['5707', '1703', 'j', '9149', '3707', 'd', 'o', 'e', 'e', '6263', 'p', '3287', '431', 't', '1419', 'a', '5481', '2093', '9249', '9665', 'd', 'j', 'k', '6925', 'a', 's', 'e', 'q', '3425', '8125', 'c', 'a', 'c', '7103', 'm', 'n', 'i']

a, c, d, e, i, j, k, m, n, o, p, q, s, t