-module('Main').
-export([main/1]).

main(_) ->
    {ok, [S]} = io:fread("", "~s"),
    Char = lists:nth(1, S),
    case lists:member(Char, lists:seq($A, $Z)) of
        true ->
            io:format("A~n");
        false ->
            io:format("a~n")
    end,
    halt().