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: ['4123', '1397', '103', 'w', 't', 'j', '233', '7239', 'b', 'n', 't', '6273', 'l', '1167', '8389', '5609', '9029', '7741', 'o', 'p', '6547', '5593', 'd', '8401', 's', '4243', 's', 'u', 'm', '6659', '5691', '2105', '8897']

SOLUTION: b, d, j, l, m, n, o, p, s, t, u, w

PROBLEM: ['h', 'l', 'i', '1507', 'h', '409', '6777', 'u', '5563', '6113', '6513', '9949', '461', 'z', 'm', '2519', 'r', '4699', 'n', 'x', '4645']

SOLUTION: h, i, l, m, n, r, u, x, z

PROBLEM: ['9593', '1765', '3065', 'p', '3343']

SOLUTION:
p