#include<iostream>
#include<cmath>
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 dot = (xa-xb)*(xc-xd) + (ya-yb)*(yc-yd);
        if(fabs(dot) < 1e-10)cout<<"YES"<<endl;
        else cout<<"NO"<<endl;
    }
    return 0;
}