instruction:
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:
['5161', 'v', 'y', '6005', 'y', 'l', '5451', 'z', 'j', 'd', '4597', '9319', '1241', 'g', 'f', 'b', 'g', '683', '763', 'm']
answer:
b, d, f, g, j, l, m, v, y, z


question:
['n', 'y', '7087', '9539', 'x', 'i', 'w', '7237', '8613', 'k', '5999', '4179', 'o', 'm', '7485', '1955', 'w', '1451', 'h']
answer:
h, i, k, m, n, o, w, x, y


question:
['u', 'r', '3579', '3939', '6783', '2363', '5055', 'l', 't', '1173', '4545', 'b', '551', '7573', 'a', 'p', 'a', '4925', '979', 'o', '1987', 'o', 'j', '3133', '6921', '4503', 'e', '2397', '5837', '7707', 'h', 'z', '1053', 'z', '5691', 't', 'i', '2927', '729', 'b', 'y']
answer:

a, b, e, h, i, j, l, o, p, r, t, u, y, z