#include <iostream>

using namespace std;

class Vector{
public:
	double x,y;

	Vector( double dx, double dy ) : x( dx ), y( dy ) {}
	Vector(){}

	Vector& operator-=( const Vector& rhs ){
		x -= rhs.x; y -= rhs.y;
		return *this;
	}
	double operator*( const Vector& rhs ){
		return x * rhs.x + y * rhs.y;
	}
};
int main(int argc, char const* argv[])
{
	Vector A,B,C,D;

	while( cin >> A.x >> A.y >> B.x >> B.y >> C.x >> C.y >> D.x >> D.y ){
		B -= A;
		D -= C;

		if( B * D == 0 ) cout << "YES" << endl;
		else cout << "NO" << endl;
	}


	return 0;
}