"If she can't solve this math problem, then I want you to cut off her arm,"

Emperor Yingjie commanded sternly, secretly fidgeting with his fingers behind his back. It's understandable, given the circumstances. You are a time traveler from the year 2207 who accidentally traveled back to 735 AD.

Taken forcefully by his guards, you naturally want to prove that you mean no harm. Emperor Yingjie will only believe you if you can solve a math problem that even his best mathematician can't solve. All eyes are on you.

"You have 2 minutes."