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: ['j', '425', '6223', '6631', 'y', '7649', 'r', 'a', '7933', '7947', 'l', 'l', '8755', 'g', 'b', '3351', '49', 'v', 'm', 'x', '3291', '1007', '1401', 'z', 'q', 'a']

SOLUTION: a, b, g, j, l, m, q, r, v, x, y, z

PROBLEM: ['m', 'z', 'd', '4667', 'v', '2881', '887', 's', '9861', 'd', '8821', '125', 't', '4493', '6749', '2983', '309', '6033', 'i', '3421', 'j', '4001']

SOLUTION: d, i, j, m, s, t, v, z

PROBLEM: ['9985', '8421', 'h', 'e', 'x', '3925', 'v', 'y', 'y', '3385', 'k', 'j', 'm', '8351', 'o', '867', '161', 'q', 'q', '5055', 'c', 's', '2553', '107', 'u', 'f', 'y', 'h', '6855', '6553', 'b']

SOLUTION:
b, c, e, f, h, j, k, m, o, q, s, u, v, x, y