   return result;
 }
 
-String forward()
+String forward(int speedInP87ercentage)
 {
   turnMotorsOn();
   

  return "ok";
}

String checkBatteryStatus()
{
  return "battery status is " + String(random(0, 1));
}

  int argument = getArgumentFromInput(input);
  
  if(command == "check battery status") {
    result = checkBatteryStatus(argument);
  } else if(command == "forward") {
    result = forward(argument);
  } else if(command == "backward") {
    result = backward(argument);
  } else if(command == "left") {
    result = left(argument);
  } else if(command == "right") {
    result = right(argument);
  } else if(command == "stop") {
    result = halt(argument);
  } else {
    result = "unknown command: " + command + ", arg: " + argument;
  }
