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.

['p', '9641', '8515', '1207', 'd', 'j', '6617', '5529', 'g', 'a', 'o', 'f', 'y', '4993', '4643', '6087', 'n', '3177', 'y', '9471', '1229', '8211', '7079']
a, d, f, g, j, n, o, p, y

['1799', '6409', '9257', '5923', 'm', 'j', '2565', '715']
j, m

['b', 'o', '6927', 't', '6109', '9921', '1747', 'p', 'o', '3055', 'v', '2865', 'k', 'z', '8039', 's', '3871', 'h', 'd', '3671', 'i', 'u', 'z', '9611']

b, d, h, i, k, o, p, s, t, u, v, z