void setup() {
  // put your setup code here, to run once:

  pinMode(2, INPUT_PULLUP);
  pinMode(3, OUTPUT);

}

void loop() {
  // put your main code here, to run repeatedly:
  if (!digitalRead(2)) {
    digitalWrite(3, HIGH);
    delay(500);
  }
  else {
    digitalWrite(3, LOW);
  }

}