What is an oval yellow pill with 36 01 on one side and a v on the other?

The oval yellow pill marked with "36 01" on one side and a "V" on the other is identified as Diphenhydramine Hydrochloride 25 mg, which is an over-the-counter antihistamine. It is commonly used to relieve symptoms of allergy, hay fever, and the common cold, such as runny nose, sneezing, and itching. Additionally, it can be used as a sleep aid due to its sedative properties. Always consult a healthcare professional before use.