const int ledMerah = 8;
const int ledBiru = 9;
const int buzzer = 10;

void setup() {
  pinMode(ledMerah, OUTPUT);
  pinMode(ledBiru, OUTPUT);
  pinMode(buzzer, OUTPUT);
}

void loop() {
  digitalWrite(ledMerah, HIGH);
  digitalWrite(ledBiru, LOW);
  tone(buzzer, 1000);
  delay(300);

  digitalWrite(ledMerah, LOW);
  digitalWrite(ledBiru, HIGH);
  tone(buzzer, 800);
  delay(300);
}