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', 'p', '8333', '8079', '4703', '7089', '8859', 'b', 'y', 'g', '7971', '6999', '2011', 'k', 'e', '9609', '4179', '3993', 'u', '3957', '6313', '4229', 'k', '5963', 'e', 'y', 'r', 'e', 'a', '2213', 'e', 'i', 'f', '7979', 'r', 'a', 'h', 'e', 'n']

SOLUTION: a, b, e, f, g, h, i, j, k, n, p, r, u, y

PROBLEM: ['j', '917', 'w', 't', '8873', '1431', '8059', '7041']

SOLUTION: j, t, w

PROBLEM: ['2675', '3291', 'k', 'v', 'k', '2609', 'z', 'b', '2163', '6895', 't', 'y']

SOLUTION:
b, k, t, v, y, z