void setup() {
  // put your setup code here, to run once:
pinMode(7, INPUT);
pinMode(8, INPUT);
pinMode(9, INPUT);
}

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

  digitalWrite(7,HIGH);
  digitalWrite(8, LOW);
  digitalWrite(9, LOW);
  delay(2000);

  digitalWrite(8, HIGH);
  digitalWrite(9, LOW);
  digitalWrite(7,LOW);
  delay(900);

  digitalWrite(9, HIGH);
  digitalWrite(7,LOW);
  digitalWrite(8, LOW);
  delay(2000);
  
}