An American, an Australian and an Irishman are POWs in a prison camp during WW2. (Since the Germans fairly well observed the Geneva Conventions, I'll let you guess where they were)

The camp commandant informs the three that unless all three can display a total of 20" of dick -they will be executed.

All three men meet the requirement.

Later, talking among themselves, the Aussie says: " Lucky for you guys that I had 10".

The American says:" Don't forget that I added 8".

The Irishman says: " Lucky for you guys I had a hard on!"