Three men wanted to join the army, so they all went to the army major and asked if they could join the ranks. The army major said "If you go back and blow up a building and tell me how many letters there are in the alphabet, then you can join."

So the first man went and blew up a building and said "Sir there are 26 letters in the alphabet." And so the major let him in.

The second man went and blew up a building and said "Sir there are 26 letters in the alphabet." And so he joined the ranks too.

The third man went and blew up a building and said "Sir there are 24 letters in the alphabet." The army major said "Why is that?" And the man said "Because I just blew up B&Q."