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.

['o', '1099', 'r', '8995', 'o', '2909']
o, r

['3611', '6825', 'j', 'e', 'r', 'a', '8889', 'y', 'x', 'k', '2651', '4545', '2289', 'r', 'q', '3163', 'a', 'i', 'j', 't', 'b', '2673', '4307', 'q', '5839', 'w', 'g', '6221', 'g', 'h', 'h', '5815', 'n', '3551', '7709', 'z', '2281', '7987', 'w', 'a', '2319', '3337', '3409']
a, b, e, g, h, i, j, k, n, q, r, t, w, x, y, z

['7939', '1861', '6023', 'n', '5563', 'b', '2767', '2437', 'p', '1653', 'n', '9209', 'l', '6399', '5181', '6141', '2799', 'i', '1099', '3945', 'j', '8747', '9025', 'c', 'x', 'o', '6979', '7621', 'e', '1921', '1395', 'b', '9075', 'a']

a, b, c, e, i, j, l, n, o, p, x