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: ['3627', '2051', '3203', 'c', 'r', 'a', '1453', 'e', 'z', 't', '1093', '4651', 'a', 'f', '8159', '9623', 'l', 't', 'r', '6963', '7071', '8103', '3493', 'y', '2369', '609', '2011', 'f', '187', 'f', 'c']

SOLUTION: a, c, e, f, l, r, t, y, z

PROBLEM: ['s', '2507', '3091', 'g', '7643', '2573', 'w', 'r', '1977', 'q', 'c', 'j', '1335', '9671', '7317', '567', '2041', '5777', 'w', 'm']

SOLUTION: c, g, j, m, q, r, s, w

PROBLEM: ['y', '1005', 'o', 'y', '6865', '7395', '8769', '9365', 'j', 'w', '5423', '3369', '2737', 'l']

SOLUTION:
j, l, o, w, y