I asked a more verbose version of the same question, and it started with a similar answer but added this:
[Edit]
In the comments, someone pointed out there were actually three answers - one was 5; the other two being 1 and 2. Because these numbers work out at the same value when they are multiplied by 6, I have changed my answer to include all three possibilities.
That was the best one I could get. It goes completely off the rails even with the temperature quite low.