Imagine that you've been diagnosed with a rare disease. Your physician prescribes you two medications—call them A and B. Each bottle contains three tablets, and both medication types have exactly the same size, shape, color, and smell. Each bottle is marked with the medication type, one bottle with A and the other B, but the pills themselves aren't marked. You're instructed to take one A tablet and one B tablet every day for 3 days. Following the instructions exactly will cure you completely, but following the instructions incorrectly leads to sudden death.
The first day, you take one A tablet and one B tablet. The next day, you discover that someone has tampered with your bottles: bottle B is empty, bottle A contains one tablet, and three tablets lie on the counter. You realize that one A tablet and two B tablets are now mixed on the table, but you can't tell which is which. You call your pharmacy and learn that the tablets are out of stock until tomorrow. How can you continue following the instructions correctly and be cured?