#include <iostream>
#include <string>
#include <math.h>
#include <algorithm>


using namespace std;
int main(){

    double xA, yA, xB, yB, xC, yC, xD, yD;
    while(cin>>xA>>yA>>xB>>yB>>xC>>yC>>xD>>yD){
//        double tan1 = atan((yA-yB)/(xA-xB));
//        double tan2 = atan((yC-yD)/(xC-xD));
        
        if((yA-yB)*(yC-yD)==-1.0*(xA-xB)*(xC-xD))cout<<"YES"<<endl;
        else cout<<"NO"<<endl;

        
//        double deg = tan1-tan2;
//        //cout<<deg<<endl;
//        if(deg==M_PI_2||deg==-M_PI_2)cout<<"YES"<<endl;
//        else cout<<"NO"<<endl;
    }
}