#include <iostream>
using namespace std;

class Vector2{
public:
	Vector2() : x( 0 ), y( 0 ){}
	Vector2( double x, double y ){
		this->x = x;
		this->y = y;
	}

	double dot( Vector2& a ){
		return ( x * a.x ) + ( y * a.y );
	}

	double x, y;
};

int main(){
	Vector2 a, b, c, d;

	while ( cin >> a.x >> a.y >> b.x >> b.y >> c.x >> c.y >> d.x >> d.y ){
		Vector2 ab( b.x - a.x, b.y - a.y ), cd( d.x - c.x, d.y - c.y );

		if ( !ab.dot( cd ) ){
			cout << "YES" << endl;
		}else{
			cout << "NO" << endl;
		}
	}

	return 0;
}