the shortest sentence

What is the shortest (grammatically, semantically and syntactically) correct sentence in the English language? I think it's "Be.". "Be." is shorter than "Kill." and the same length as "Do." but based on descending alphabetical order of the initial letter in each case "Be." would be at the top of the list. The sentence "I." lacks an object not to mention a verb, as do the exclamatories "O!", "Ah!" etc. So it would seem that "Be." is the winner, unless anyone can come up with another candidate?.