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', '8797', 'i', '5443', 'i', 'f', '7593', 'u', 'h', '3251', 'l', '681', 'y', 'n', 'r', '1699', '1379', '8987', '6955', 'x', 'p', 'x', '553', 'q', '5679', 'q', 'w', '9007', 'r', '8945', '7351', 'a', 'v', 'k', '1309', 'v', 'i', '4161', 'a', 'q', '2919', '6917', '6845']

SOLUTION: a, f, h, i, j, k, l, n, p, q, r, u, v, w, x, y

PROBLEM: ['749', 'r', 'a', 's', 't', '5905', 'm', 'd', '8437', '4583']

SOLUTION: a, d, m, r, s, t

PROBLEM: ['2927', 'y', 'g', '2715', 'x', '7181', 'v', '2931', '7023', 'a', 'w', '7175', 'b', '5627', '3719', 'x', '3111', 'm', 'i', '7315', 'b', 'p', '4209', 'x', 'f', '3019', 'e', '1569', 's', '8725', 'x', 'v', '219', '2065', '1143']

SOLUTION:
a, b, e, f, g, i, m, p, s, v, w, x, y