void setup()
{
  pinMode(LED_BUILTIN, OUTPUT);
  Serial.begin(921600);
  Serial.println("Hello, World!");
}

void loop()
{
  delay(5000);
  digitalWrite(LED_BUILTIN, HIGH);
  Serial.println("LED ON");
  delay(2000);
  digitalWrite(LED_BUILTIN, LOW);
  Serial.println("LED OFF");
}