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.

['7187', '7081', 'j', 'i', '3725', '6333', 'h', 'f', '6639', 'r', 'n', '3559', '2785']
f, h, i, j, n, r

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

['1819', 'y', 'r', 'z', 'o', '6901', 's', '185', 'f', '1157', 'f', 's', '3497', '8511', 'f', '6197', 'e', '7501', '7263', '4309', 'a', '4879', '1123', 'o', '6621', 'i', 'm', '7571', 'y', '5133', '4603', 'v', '8691', 'x', '9793', '371', 'b', 'l', '3745', '23', '7919']

a, b, e, f, i, l, m, o, r, s, v, x, y, z