void setup() {
  // put your setup code here, to run once:
  pinMode(8, OUTPUT);
  pinMode(9, OUTPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
    digitalWrite(8, HIGH);   // turn the LED on (HIGH is the voltage level)
    digitalWrite(9, LOW);    // turn the LED off by making the voltage LOW
    delay(1000); 
    digitalWrite(8, LOW);   
    digitalWrite(9, HIGH);
    delay(1000);

}