void setup() {
  // put your setup code here, to run once:
   Serial.begin(9600);
   if(!Serial) Serial.println("serail is not working");
   pinMode(3, OUTPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
   digitalWrite(3, HIGH);
   Serial.println("red is on");
   delay(1000);
   digitalWrite(3, LOW);
   Serial.println("red is off");
   delay(1000);
}