False. You in fact typed TWO sentences assuming that the ellipse at the end of the first line of your comment was a full sentence. However, according to the English language, because you added “then…” to the end, the sentence is now incomplete and is likely not actually a sentence in itself. Therefore, if we count it all as a single sentence or just the first line as an incomplete sentence and the second as a complete sentence, we will have one sentence either way.
Oh wait.
Oh you’re right. It is one sentence.