TASK DEFINITION: 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.
PROBLEM: ['l', '6313', '3199', 'w', '249', '8747', '7391', '3871', '173', 'x', 'o', '8647', '4413', '3645', '6123', '701', 'q', '2147', '4289', '7333', '533']

SOLUTION: l, o, q, w, x

PROBLEM: ['907', '2407', '1385', '3593', 'x', '4143', '2271', '8361', 'q', '5093', 'd', '257', 'm', 'a', '5751', '7845', '3925', '3517', '7753', 'e', '5803', '2629', 't', 'e', '845', '6157', '9787', '225', 'j', 'j', 'l', '1321', 'k', '2459', 'u', '9113', '3193', 'a', 'j', 't']

SOLUTION: a, d, e, j, k, l, m, q, t, u, x

PROBLEM: ['m', 'e', 'q', 'n', 'r', '4441', 'z', 'p', '1301', '4157', '7999', 'v', 'u', '8057', 'c', 'f', '4191', 'i', '8041', 'y', '7691', 'n', 'z', 'i', 'x', 'i', '8007', 'x', '7321', 'a', '9085', 'j', '95', '2039', 's', '763']

SOLUTION:
a, c, e, f, i, j, m, n, p, q, r, s, u, v, x, y, z