Hi. I will be arriving on a Lufthansa flight from the USA to DUS then catching a connecting flight on Aegean to Thessaloniki. I have a 4 hour layover at DUS. I assume that I will arrive in Terminal A and go to Terminal B for my connecting flight. Will there be a single security check or will there be one at each terminal. The DUS website mentions "several" checks when moving from one terminal to another.