/*#include <iostream>
using namespace std;

int main(){
	double a[8];
	while(cin >>a[0]>>a[1]>>a[2]>>a[3]>>a[4]>>a[5]>>a[6]>>a[7]){
		if((a[3]-a[1])*(a[7]-a[5])==-1*(a[2]-a[0])*(a[6]-a[4]))cout << "YES" << endl;
		else cout << "NO" << endl;
	}
	return 0;
}*/
#include<iostream>
#include<cmath>
using namespace std;
 
int main(){
    double x1,x2,x3,x4,y1,y2,y3,y4,EPS=1e-12;
    while(cin>>x1>>y1>>x2>>y2>>x3>>y3>>x4>>y4){
        if(fabs(((x2-x1)*(x4-x3))+((y2-y1)*(y4-y3)))<=EPS)cout<<"YES";
        else cout<<"NO";
        cout<<endl;
    }
}