#include<stdio.h>
double abs(double a){return a<0?-a:a;}
int main(){
	double xa,xb,xc,xd,ya,yb,yc,yd;
	while(~scanf("%lf%lf%lf%lf%lf%lf%lf%lf",&xa,&ya,&xb,&yb,&xc,&yc,&xd,&yd)){
		double t=(xa-xb)*(xc-xd)+(ya-yb)*(yc-yd);
		if(abs(t)<0.00001)printf("YES\n");
		else printf("NO\n");
	}
}