#include <iostream>
#include <string>
using namespace std;

float han(float a, float b, float c, float d, float e, float f, float g, float h){
	float ans = (c - a)*(g - e) + (d - b) * (h - f);
	return ans;
}

int main(){
	float xa[2], xb[2], ya[2], yb[2];
	while (cin >> xa[0] >> ya[0] >> xa[1] >> ya[1] >> xb[0] >> yb[0] >> xb[1] >> yb[1]){
		float ans = han(xa[0], ya[0], xa[1], ya[1], xb[0], yb[0], xb[1], yb[1]);
		if(ans == 0){
			cout << "YES" << endl;
		}
		else{
			cout << "NO" << endl;
		}
	}
	return 0;
}