#include<Servo.h>
Servo myservo;

int ldrback=A0;
int ldrmain=A1;
int threshold=510;
void setup() {
  // put your setup code here, to run once:
pinMode(ldrback,INPUT);
pinMode(ldrmain,INPUT);
myservo.attach(3);

}
int mainvalue;
int backvalue;

void loop() {
if(analogRead(ldrmain)<threshold)
{
  mainvalue=HIGH;
}
else{
  mainvalue=LOW;
}
if(analogRead(ldrback)<threshold)
{
  backvalue=HIGH;
}
else{
  backvalue=LOW;
}
  if(mainvalue==backvalue)
  {
    myservo.write(0);
  }
  else{
    myservo.write(180);
  }
}