#include <bits/stdc++.h>
using namespace std;

double eps = 1e-10;

class Point {
public:
	double x, y;
	
	Point(double x = 0, double y = 0) : x(x), y(y) {}
	
	Point operator + (const Point& p) {
		return Point(x + p.x, y + p.y);
	}
	Point operator - (const Point& p) {
		return Point(x - p.x, y - p.y);
	}
	Point operator * (const double& a) {
		return Point(x * a, y * a);
	}
	Point operator / (const double& a) {
		return Point(x / a, y / a);
	}
	
	bool operator < (const Point& p) const {
		return x != p.x ? x < p.x : y < p.y;
	}
	bool operator == (const Point& p) const {
		return fabs(x - p.x) < eps && fabs(y - p.y) < eps;
	}
	
	double abs() {
		return sqrt(norm());
	}
	double norm() {
		return x * x + y * y;
	}
	
};

typedef Point Vector;

// ????????????
bool equals(const double& a, const double& b) {
	return fabs(a - b) < eps;
}

// ??????
double dot(const Vector& a, const Vector& b){
	return a.x * b.x + a.y * b.y;	
}

// ??´?????????(????????????)
bool isOrthogonal(Vector a, Vector b){
	return equals(dot(a, b), 0.0);
}

// ??´?????????(???4???)
bool isOrthogonal(Point a1, Point a2, Point b1, Point b2){
	return isOrthogonal(a1 - a2, b1 - b2);
}

int main() {
	double x1, x2, x3, x4, y1, y2, y3, y4;
	while(cin >> x1 >> y1 >> x2 >> y2 >> x3 >> y3 >> x4 >> y4){
		if(isOrthogonal(Point(x1, y1), Point(x2, y2), Point(x3, y3), Point(x4, y4))){
			cout << "YES" << endl;
		}
		else{
			cout << "NO" << endl;
		}
	}
	return 0;
}