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.
--------
Question: ['895', '2049', '8839', '1773', 'v', '467']

Answer: v


Question: ['7917', '2295', 'q', 'v', '9373', 'w', 'n', 'q', '5803', 'g', 'k', 'm', '2167', 'k', '6425', 'x', 'g', '341', 't', 'u', '8829', 'h', '4333']

Answer: g, h, k, m, n, q, t, u, v, w, x


Question: ['a', 's', 'f', '8973', 'y', 'j', 'c', '8543', 'p', '9023', 't', 'p', 'f', '3969', '9211', '9501', '5483']

Answer:
a, c, f, j, p, s, t, y


