#include

<cstdio>

using namespace std;


double
xA,yA,xB,yB,xC,yC,xD,yD;

int
main()
{

	

while
(~scanf(

"%lf%lf%lf%lf%lf%lf%lf%lf"
,&xA,&yA,&xB,&yB,&xC,&yC,&xD,&yD))

	

{

		

if
((xB-xA)*(xD-xC)+(yB-yA)*(yD-yC)==0)printf(

"YES\n"
);

		

else
printf(

"NO\n"
);

	

}
}