void setup() {
  // put your setup code here, to run once:
 pinMode(3, OUTPUT);
 pinMode(4, OUTPUT);
 pinMode(5, OUTPUT);
 pinMode(A0, INPUT);
}

void loop() {
  int a (analogRead(A0));
  
 if (a>500){digitalWrite(3, HIGH);}
 else {digitalWrite(3,0);}

 if (a>800){digitalWrite(4, HIGH);
 }
 else {digitalWrite(4,0);}

 if (a>1000){digitalWrite(5, HIGH);
 }
 else {digitalWrite(5,0);}
 
}