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: ['3147', '9807', '5313', '6311', '737', '1555', '5803', '3437', '5665', '3973', 'o', 'f', '7871', '1721', '7833', '2933', 'b', 'b', 'n', 'm', 'k']

Output: b, f, k, m, n, o


Input: Consider Input: ['7799', '8163', '3389', 'x', 'k', 'm', '6085', 'f', '1131']

Output: f, k, m, x


Input: Consider Input: ['f', '6177', 'n', '4497', 'k', 'm', '943', 'm', '1601', 'q', 'i', 'y', 'n', '4499', 'k', '4909', '8329', '2831', 'c', 'l', 'd', 'f', 'a', 'h', '9121', '1929', '9387', 'q', 'k', 'j', 'r', 't', '5537', 'h', '6911', '7787', '5027', 'x', 'z', 'j', '2061', 'g', 'd', 'b']


Output: a, b, c, d, f, g, h, i, j, k, l, m, n, q, r, t, x, y, z