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: ['i', 'h', '8299', 'e', 'c', '5543', '5241', 'f', '3985', 'f', 'z', '1245', 'e', 't', 'g', '5199', '9217', 'q', 'j', 'p', '767', 'z', '1803', 'k', '7303', '3187', '2507', '6471', '3337', '6037', '9291', 'a', 'l']

SOLUTION: a, c, e, f, g, h, i, j, k, l, p, q, t, z

PROBLEM: ['e', '8391', '7065', '6141', '3335', 't', 'i', 'c', '1791', '6333', 'b', 'z', '1621', 'e', 'h', 'u', 'o', 'q', '3195', '6507', '3253', 'c', '2067', '3917', '7111', 'r', 'j', 'd', '3987', '9139', 'm', '981', 'l', 'f', '2417', 'w', '9983', 'h', 'd', '6021', 'a', 'f']

SOLUTION: a, b, c, d, e, f, h, i, j, l, m, o, q, r, t, u, w, z

PROBLEM: ['h', 's', '7887', 'd', '2913', 'z', '4557', 'a', '5089', 'e', '8201', 'e', '6685', '1605', 't', 'e', '5025', 'q', '3899', 'n', '9487', 'w', 'm', '7113', 'b', '4807', 'o', '8551']

SOLUTION:
a, b, d, e, h, m, n, o, q, s, t, w, z