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.

Input: Consider Input: ['6955', '721', '2763', '8121', '9109', '6341', 'p', 't', 'x', '6963', '1137', 'z', 'u', '1949', '7029', 't', '9539', 'a', 'u', '1873']

Output: a, p, t, u, x, z


Input: Consider Input: ['n', 'w', '6735', '3427', '6115', 'q', '7851', '3645', 'g', '6825', '6515', '4885', 'z']

Output: g, n, q, w, z


Input: Consider Input: ['r', '4841', 'j', '1103', '6705', '4649', 'f', 'r', 'q', 'w', 'o', 's', 'l', '8873', '1705', '6915', '6445', 'v', '7449', 'g', '1549', 'a', 'o', 't', 'n', '7001', 'j', '3863', '7259', '4359', 'r', '9269', 'w', '6603', 'u', 'o', 'f', '8119', 'k', '5279', 'o']


Output: a, f, g, j, k, l, n, o, q, r, s, t, u, v, w