$\textbf{Mixed Pills}$

John must take exactly one $A$ pill and one $B$ pill each day. These two types of pills look exactly the same and cannot be distinguished in any way. One day, while he has one $A$ pill in his hand, he accidentally gets two $B$ pills out of the bottle. Now he has three indistinguishable pills in his hand. As both medicines are quite expensive, John does not want to waste any pill. What can he do?