#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==0&&yd-yc==0) cout<<"YES";
    else if(yb-ya==0&&xd-xc==0) cout<<"YES";
    else if((xb-xa)*(yd-yc)==0||(yb-ya)*(xd-xc)==0) cout<<"NO";
    else if(((yb-ya)/(xb-xa))==(-(xd-xc)/(yd-yc))){
      cout<<"YES";
    }
    else cout<<"NO";
    cout<<endl;
  }
  return 0;
}