CF851B Arpa and an exam about geometry

Arpa is taking a geometry exam. Here is the last problem of the exam. You are given three points $ a,b,c $ . Find a point and an angle such that if we rotate the page around the point by the angle, the new position of $ a $ is the same as the old position of $ b $ , and the new position of $ b $ is the same as the old position of $ c $ . Arpa is doubting if the problem has a solution or not (i.e. if there exists a point and an angle satisfying the condition). Help Arpa determine if the question has a solution or not.

The only line contains six integers $ a_{x},a_{y},b_{x},b_{y},c_{x},c_{y} $ ( $ |a_{x}|,|a_{y}|,|b_{x}|,|b_{y}|,|c_{x}|,|c_{y}|

Print "Yes" if the problem has a solution, "No" otherwise. You can print each letter in any case (upper or lower).

In the first sample test, rotate the page around $ (0.5,0.5) $ by . In the second sample test, you can't find any solution.