#include<cstdio>
#include<cmath>
struct Point
{
	double x,y;
};
int main(void)
{
	Point a,b,c,d;
	scanf("%lf %lf",&a.x,&a.y);
	scanf("%lf %lf",&b.x,&b.y);
	scanf("%lf %lf",&c.x,&c.y);
	scanf("%lf %lf",&d.x,&d.y);
	Point vec1,vec2;
	vec1.x=b.x-a.x;vec1.y=b.y-a.y;
	vec2.x=d.x-c.x;vec2.y=d.y-c.y;
	if((float)atan2(vec1.y,vec1.x)==(float)atan2(vec2.y,vec2.x))
	{
		printf("YES\n");
	}
	else
	{
		printf("NO\n");
	}
	return 0;
}