#include <iostream>
#include <cfloat>
using namespace std;


//0058
int main(){
	double xA, yA, xB, yB, xC, yC, xD, yD;
	char ch;
	while(cin >> xA >> yA >> xB >> yB >> xC >> yC >> xD >> yD){
		double x1,y1,x2,y2, d1,d2, e;
		y1=yB-yA;
		x1=xB-xA;
		y2=yD-yC;
		x2=xD-xC;

		if(-(y1*y2)-DBL_EPSILON < (x1*x2) 
			&& (x1*x2) < -(y1*y2)+DBL_EPSILON){
			cout << "YES" << endl;
		}else{
			cout << "NO" << endl;
		}

	}

}