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.

Example Input: ['c', '7039', 'g', '1899', 'r', '507', 'c', '2587', '3865', '1729', '3927', 'r', '3535', '2791', 'm', 'l', 'r']
Example Output: c, g, l, m, r

Example Input: ['l', 'o', 's', '7411', '7847', '2557', '1977', '2863', '2325', '4177', '4183', '4241', '1005', '1137', '1371', 'v', 'p', 'a', '2453', 'l', '6315', 'l', '6463', 'n', '7645', '9669', '5411', '1631', '5995', 'z', '227']
Example Output: a, l, n, o, p, s, v, z

Example Input: ['t', 'f', 'p', '5727', 'i', '3971', 'j', '7751', '8869', '6297', 'p', '155', 'p', '3201', 't', 'z', '6347', 'f', '1949', 'u', 'i', '9721', 'x']
Example Output:
f, i, j, p, t, u, x, z