#define BUTTON_PIN 4

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

void loop() {
  // put your main code here, to run repeatedly:
  int value = digitalRead(BUTTON_PIN);
  if (value == HIGH){
    digitalWrite(LED_BUILTIN, LOW);
  }
  if (value == LOW){
    digitalWrite(LED_BUILTIN, HIGH);
  }
}