https://www.gkbymrdj.com/a-man-walks-1-km-to-east-and-then-he-turns-to-south-and-walks-5-km-again-he-turns-to-east-and-walks-2-km-after-this-he-turns-to-north-and-walks-9-km-now-how-far-is-he-from-his-starting-point/