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: ['8821', '9833', 'l']

Output: l


Input: Consider Input: ['5859', 'x', 'z', 'v', 'l', 'z', 'g', 't', 'x', '341', '7023', '4937', 'b', 'n', 'y', 't', 's', '1369', '4461', 'f', '1315', 'l', '5221', '6583', 'h', 'j', 't']

Output: b, f, g, h, j, l, n, s, t, v, x, y, z


Input: Consider Input: ['m', '1555', 'w', 'i', 'o', '6733']


Output: i, m, o, w