So if you look at an 18-hour half-life, what you're basically saying is that every 18 hours, the virus--it's the life of the virus is cut in half. So if you start with 1,000 particles of the virus, in 18 hours, you're down to 500. And 18 hours after that, you're down to 250, and so on and so forth. That's important, as I explain in the rest of the chart.