int LED_Red = 23;
int LED_Yellow = 19;
int LED_Green = 18;

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

void loop() 
{// put your main code here, to run repeatedly:

  digitalWrite(LED_Red, LOW);
  digitalWrite(LED_Yellow, LOW);
  digitalWrite(LED_Green, LOW);
  delay(1000);
  digitalWrite(LED_Red, HIGH);
  digitalWrite(LED_Yellow, HIGH);
  digitalWrite(LED_Green, HIGH);
  delay(1000); 
}