4 days. That's some of the busiest days of my life. It was tough because throughout it all, I had to be able to think clearly and function normally especially during crunch time - that was the last of those 4 days. It was non-stop working and major deadlines, crucial reports, etc.
By the 4th day, there was a little window where I could nap, and I really wasn't functioning anymore, I couldn't even figure out how to open this attachment that was sent to me so I took a nap, and I slept so soundly i didn't wake even if 4 people tried to wake me up because of some very important calls. I missed the calls and woke up 3 hours later and it was back to work for another 3 days.