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: ['1487', '8003', 'd', '7237', 'l', 'y', '2749', 'e', '9685', '2825', 'z', '7743', 'r', '9617', 'w', '4323', '2173', '8419', '2831', '8923', 'l', '2985', '303', 'y', '9409', 'i', 'h', 'e']

SOLUTION: d, e, h, i, l, r, w, y, z

PROBLEM: ['m', '6761']

SOLUTION: m

PROBLEM: ['k', '3983', 'p', '8839', 'c', '2145', 'h', 'u', '3369', '5541', 'y', 'k', '7337', 't', 'p', 'z', '245', '1971', '1635', '9995', 'c', 'r', '5845', 'j', '8777', 'c', '5557', '5203']

SOLUTION:
c, h, j, k, p, r, t, u, y, z