#include<stdio.h>

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)){
		if((ya-yb)*(yd-yc)==-(xd-xc)*(xa-xb))printf("YES\n");
		else printf("NO\n");
	}
	return 0;
}