begin
writeln('(0, 0)');
writeln('(1, 0)');
writeln('(2, 0)');
writeln('(2, 1)');
writeln('(2, 2)');
writeln('(2, 3)');
writeln('(2, 4)');
writeln('(3, 4)');
writeln('(4, 4)');
end.
————————————————————
终于看到POJ的良心………………