#include<cstdio>
#include<cstdlib>
using namespace std;
int main(){
	
	double xA,yA,xB,yB,xC,yC,xD,yD;
	
	while(scanf("%lf%lf%lf%lf%lf%lf%lf%lf",&xA,&yA,&xB,&yB,&xC,&yC,&xD,&yD) != EOF){
		
		double a,b,c,d;
		
		a = (yA-yB);
		b = (xA-xB);
		c = (yC-yD);
		d = (xC-xD);
		
		(a*c + b*d == 0) ? puts("YES") : puts("NO");
	}
	
	return 0;
}