void setup() {
  // put your setup code here, to run once:
pinMode(3, OUTPUT);
pinMode(7, INPUT_PULLUP);

}

void loop() {
  // put your main code here, to run repeatedly:
  int b = digitalRead(7);

  if(b == LOW){
    digitalWrite(3, HIGH);

  }
  else{
    digitalWrite(3, LOW);
  }
}