int led1 = 10; 
int led2 = 9; 
int led3 = 8; 
int delayTime = 500;

void setup() {
  pinMode(led1, OUTPUT);
  pinMode(led2, OUTPUT);
  pinMode(led3, OUTPUT);
  
  Serial.begin(9600);
}

void loop() {
  // Nyalakan LED 1
  digitalWrite(led1, HIGH);
  Serial.println("LED 1 menyala");
  delay(delayTime);

  // Matikan LED 1
  digitalWrite(led1, LOW);
  Serial.println("LED 1 mati");
  delay(delayTime);

  // Nyalakan LED 2
  digitalWrite(led2, HIGH);
  Serial.println("LED 2 menyala");
  delay(delayTime);

  // Matikan LED 2
  digitalWrite(led2, LOW);
  Serial.println("LED 2 mati");
  delay(delayTime);

  // Nyalakan LED 3
  digitalWrite(led3, HIGH);
  Serial.println("LED 3 menyala");
  delay(delayTime);

  // Matikan LED 3
  digitalWrite(led3, LOW);
  Serial.println("LED 3 mati");
  delay(delayTime);
}