4 liters of water per day, plus B12 and C vitamins

I read that a man has to drink about 3-4 liters of water per day.

My brain is big, so I guess I am more in the 4-5 liters category.

Anyway,

I am awake for 12 hours.

I need to drink 4 liters of water daily.

Per hour, that is

4000 / 12 = 333

So I need to drink 333 mililiters of water every hour.

However, I chose to drink water every 2 hours.

So I need to drink 666 mililiters of water every 2 hours for 12 hours to drink 4 liters of water daily.

I also read that B12 vitamin is very important for brain. So I figured, if I take lots of Vitamin B12, my brain power could even be restored to its former glory.

https://www.gigacalculator.com/calculators/water-intake-calculator.php 

Although there is an average, a doctor would help identify a more exact number. Pretty sure the measurements is not in liters. 

I dont trust doctors. They work for the scientific community.

Okay, your calculator says about 2 liters, which is too little.

Fix your calculator.