int Bpin = 3;
int Lpin = 11;
bool state = 0;
void setup() {
  // put your setup code here, to run once:
  pinMode(Lpin, OUTPUT);
  pinMode(Bpin, INPUT);
  Serial.begin(9600);
}

void loop() {
  // put your main code here, to run repeatedly:
  state = digitalRead(Bpin);

  if (state==HIGH){
    digitalWrite(Lpin, HIGH);
  }
  else {
    digitalWrite(Lpin,LOW);
  }
}