
main(){
  double xa, ya, xb, yb, xc, yc, xd, yd;
  double A,B;//AAB
  while((scanf("%lf%lf%lf%lf%lf%lf%lf%lf",&xa,&ya,&xb,&yb,&xc,&yc,&xd,&yd))!=EOF){
    // cout << xa << " "<<ya << " " << yd<< endl;
    
    if((xa-xb) != 0){A=(ya-yb)/(xa-xb);}
    if((xc-xd) != 0){B=(yc-yd)/(xc-xd);}
    
    
    if(A*B==-1){cout << "YES"<<endl;}
    else if((xa-xb)==0 && (ya-yb)==0 ||(xc-xd)==0 && (yc-yd)==0 ){cout << "YES"<<endl;}
    else if((xa-xb)==0&&(xc-xd)==0){cout << "NO"<<endl;}
    else if((xa-xb)==0&&B==0){cout << "YES"<<endl;}
    else if((xc-xd)==0&&A==0){cout << "YES"<<endl;}
    else {cout << "NO"<<endl;}

  }
    
  return 0;
 
 
}