#include<iostream>
using namespace std;
int main(){
    double xa,ya,xb,yb,xc,yc,xd,yd;
    while(cin>>xa>>ya>>xb>>yb>>xc>>yc>>xd>>yd){
//        if(!((xb-xa)*(xd-xc)+(yb-ya)*(yd-yc)))cout<<"YES"<<endl;
//        else cout<<"NO"<<endl;
        !((xb-xa)*(xd-xc)+(yb-ya)*(yd-yc))?cout<<"YES"<<endl:cout<<"NO"<<endl;
    }
}