int buttonStatus = LOW;

void setup() {
    pinMode(LED_BUILTIN, OUTPUT);
  pinMode(2, INPUT);
}

void loop() {
  buttonStatus = digitalRead(2);
  if (buttonStatus == HIGH) {
    digitalWrite(LED_BUILTIN, HIGH);
    delay(500);
  }
  digitalWrite(LED_BUILTIN, LOW);
  delay(500);
}