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.

['815', '6967', '6553', 'r', 'y', '3641', 'q', 'b', '6131', '4289', 'w', '6093', '6055', 'i', 'b', 'y', '5107', 'v', 'g', '9709', 'x', 'i']
b, g, i, q, r, v, w, x, y

['n', 'g', 'u', '2873', 'k', '4411', 'w', '8179', 'w', 'w', 'f', 'g', 'e', '7837', '3055', 'z', 's', '6037', 'n', '1479', 'c', '5311', 'i', 'w', 'z', '1891', '9663', 'y', 'f', 'h']
c, e, f, g, h, i, k, n, s, u, w, y, z

['411', 'o', '1419', 'g', '2283', '7753', '143', '6413', 'r', 'p', '9351', '6247', 'q', '8913', '455', '3581', '7703', 'r', '8153', 'a', 'q', '2659', 'e', '9211', 'x', 'p', 'i', 'l', '577', '6859', 'r', 'v', 'z', 't', '3239', '4161', '5371', '2477', '7993', 'q', 'c', 'h', '265', '163']
a, c, e, g, h, i, l, o, p, q, r, t, v, x, z