#include <iostream>
#include <stdio.h>
using namespace std;

int main() {
	double ax,ay,bx,by,cx,cy,dx,dy,ex,ey,fx,fy; 
	while(cin >>ax >> ay >> bx >> by >> cx >> cy >> dx >> dy) {
		ex=ax-bx; ey=ay-by; fx=cx-dx; fy=cy-dy;
		if (ex*fx+ey*fy==0) cout << "YES" << endl; else cout << "NO" << endl;
	}
	return 0;
}