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: ['m', '6761']
Example Output: m

Example Input: ['6209', 'x', 'j', 'w', '7965', '4905', '6297', '4291', '7183', 'a', 'l', '5267', 'r', '5935', 'a', '7865', 'h', 'p', '6117', 'a', 'y', 'y', 't', 'v', '7271', 'e', 'e', 'z', 'i', 'l', '4731', '2059', 'm', '5703', 'k', 'f', '8125', 'e', '7569', 'r', '2287', '593']
Example Output: a, e, f, h, i, j, k, l, m, p, r, t, v, w, x, y, z

Example Input: ['m', 'd', 'n', 'g', '7297', 'l', '1385', '8439', '7497', '6779', 'u', '7063', '1765', 'q', '9501', 'v', 'w', '1077', '457', '9859', 'f', '1781', 'e', 'm', '7655', 'z', '5589', '3205', 'f', 'i', 'z', '7073', 'q', '8029', 'd', 'z', '1739', '7503', '8341', 'o', 'd', 'd']
Example Output:
d, e, f, g, i, l, m, n, o, q, u, v, w, z