I had trouble falling asleep...
...So the doctor told me about an experimental new drug. "It's very new," the doctor said, "It doesn't even have a name yet, we just call it Pill M."
Alas, after a week of use, I still had trouble falling asleep, so I went back to the doctor's
"Ah you came just in time," the doctor began, "we created a brand new formula, stop using Pill M, and start using Pill O"