void setup() {
  // put your setup code here, to run once:
pinMode(9, OUTPUT);
pinMode(3, INPUT);

}

void loop() {
  // put your main code here, to run repeatedly:
if (digitalRead(3) == HIGH) {
digitalWrite(9, LOW);
delay(500);
digitalWrite(9, HIGH);
delay(500);
}else {
digitalWrite(9, LOW);
}
}