const int BUTTON = 2;
int val;

void setup() {
  // put your setup code here, to run once:
  pinMode(BUTTON, INPUT);
  pinMode(LED_BUILTIN, OUTPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
  val = digitalRead(BUTTON);
  if(val == 1){
    digitalWrite(LED_BUILTIN, HIGH);
    delay(300);
    digitalWrite(LED_BUILTIN, LOW);
    delay(300);
  }
  else{
    digitalWrite(LED_BUILTIN, HIGH);
  }
}