int ledPin = 2;
int butPin = 3;
void setup() {
  // put your setup code here, to run once:
pinMode(ledPin, OUTPUT);
pinMode(butPin, INPUT_PULLUP);
}

void loop() {
  // put your main code here, to run repeatedly:
if (digitalRead(butPin)){
  digitalWrite(ledPin, LOW);
}
else {
  digitalWrite(ledPin, HIGH);
}
}