#include<iostream>
#include<iomanip>
#include<vector>
#include<queue>
#include<list>
#include<stack>
#include<algorithm>
#include<cmath>
#include<memory>

using namespace std;

class Vector
{
public:
  double x;
  double y;

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

  Vector operator + ( const Vector v ) { return Vector( x + v.x, y + v.y ); }
  Vector operator - ( const Vector v ) { return Vector( x - v.x, y - v.y ); }
  Vector operator * ( const double k ) { return Vector( x * k, y * k ); }
  Vector operator / ( const double k ) { return Vector( x / k, y / k ); }
  bool operator < ( const Vector &v ) const { return x * x + y * y < v.x * v.x + v.y * v.y; }

  double abs() { return sqrt( norm() ); }
  double norm() { return x * x + y * y; }

  static double dot( Vector v1, Vector v2 ) { return v1.x * v2.x + v1.y * v2.y; }
  static double cross( Vector v1, Vector v2 ) { return v1.x * v2.y - v1.y * v2.x; }
};

int main()
{
  const double eps = 1e-10;

  Vector a, b, c, d;
  
  while ( cin >> a.x >> a.y >> b.x >> b.y >> c.x >> c.y >> d.x >> d.y )
    {
      if ( fabs( Vector::dot( b - a, d - c ) ) < eps )
        cout << "YES" << endl;
      else
        cout << "NO" << endl;
    }
  
  return 0;
}