int LDR=A0;
int LED=9;
void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);
  pinMode(LDR,INPUT);
  pinMode(LED,OUTPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
  int ldr=analogRead(LDR);
  if(ldr<300){
    digitalWrite(LED,HIGH);
  }
  else{
    digitalWrite(LED,LOW);
  }
}