Give me some Mountain Dew, Howling Monkeys (Best energy drink ever! & the Cola brand of course), and some food, I would finish in about four days at the most. I know my head would be drained and in pain then, but still.
Throw out some inaccurate math here. Naruto chapters are on average 20 pages and a fast reader like myself can finish the chapter in 3 minutes. Now double that for a forty page chapter and its six minutes. So 6 times 899 equals 5394 minutes or roughly 89.9 hours or roughly 3.75 days. That's your answer if you're a fast reader. Variable you would have to calculate personally is how many pages will have picture only panels and how much time it takes you to read a chapter.