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: ['3307', 'r', '2665', '3453', 'f', 'd', 'v', '3801', '3153', '3137', 'y', 'i', '9681', 'k', '9253', 'y', 'i', '8631', '2375', '5131', 'r', 'z', '8645', '595', 's', '6749', '2665', '709', '8203']

SOLUTION: d, f, i, k, r, s, v, y, z

PROBLEM: ['h', 'u', 'y', '7677', '9441', '1769', 'v', '1433', 'l', '7739', 'a', '8305', 'n', 'a', '6711', '3161', 'e', 'u', '993', '2211', '4011', 'q', 'o']

SOLUTION: a, e, h, l, n, o, q, u, v, y

PROBLEM: ['4191', '6411', '8581', 'l', '3697', 'h', 'c', 'g', 'e', '8129', '3391', '5027', 'e', '33', '2631', '7435', 't', 'o', '9173', '8957', '2623', '5329']

SOLUTION:
c, e, g, h, l, o, t