const int led=13;
const int ldr=A3;
void setup() {
  Serial.begin(9600);
  pinMode(led,OUTPUT);
  pinMode(ldr,INPUT);
}
void loop() {
  int ldrSt=analogRead(ldr);
  if (ldrSt>=400){
    digitalWrite(led,1);
    Serial.print("It's DARK, Turn on the LED :");
    Serial.println(ldrSt);  
    }
    else {
      digitalWrite(led,0);
      Serial.print("It's Bright, Turn off the LED :");
      Serial.println(ldrSt);
      }
}