int merah = 16;
  int kuning = 17;
  int hijau = 18;

void setup() {
  // put your setup code here, to run once:
  
  Serial.begin(115200);
  pinMode(merah, OUTPUT);
  pinMode(kuning, OUTPUT);
  pinMode(hijau, OUTPUT);
  Serial.println("Hello, ESP32!");
}

void loop() {
  // put your main code here, to run repeatedly:
  digitalWrite(merah, HIGH);
  digitalWrite(kuning, LOW);
  digitalWrite(hijau, LOW);
  delay(1000); // this speeds up the simulation
  digitalWrite(merah, LOW);
  digitalWrite(kuning, HIGH);
  digitalWrite(hijau, LOW);
  delay(1000);
  digitalWrite(merah, LOW);
  digitalWrite(kuning, LOW);
  digitalWrite(hijau, HIGH);
  delay(1000);
}