#include<iostream>
using namespace std;

class Point{public:double x,y;};
class Vector{public:double x,y;};

int main(void){
	while( true ){
		Point a, b, c, d;
		Vector vAB, vCD;
		double production;

		cin >> a.x >> a.y >> b.x >> b.y >> c.x >> c.y >> d.x >> d.y;
		if(cin.eof())break;
		
		vAB.x = a.x - b.x;
		vAB.y = a.y - b.y;
		vCD.x = c.x - d.x;
		vCD.y = c.y - d.y;
		production = vAB.x * vCD.x + vAB.y * vCD.y;
		
		if( production == 0 ) cout << "YES" << endl;
		else cout << "NO" << endl;
	}
	return 0;
}