int counter = 1;

//leds
int l1 = 2;
int l2 = 3;
int l3 = 4;

//BUTTON
int buttonL = 5;
int buttonR = 6;

void setup() {
  // put your setup code here, to run once:
pinMode(l1,OUTPUT);
pinMode(l2,OUTPUT);
pinMode(l3,OUTPUT);

pinMode(buttonL,INPUT);
digitalWrite(buttonL,HIGH);
  
pinMode(buttonR,INPUT);
digitalWrite(buttonR,HIGH);  
  
Serial.begin(9600);
}

void loop() {
  //Serial.println(counter);
  Serial.println(digitalRead(buttonR));
  if (digitalRead(buttonL) == 0){
      while (digitalRead(buttonL) == 0){}
      if (counter - 1 == 0){
        counter = 3;
        }
      else{
        counter = counter - 1;
        }     
    }
    
    if (digitalRead(buttonR) == 0){    
      while (digitalRead(buttonR) == 0){Serial.println(digitalRead(buttonR));}      
      if (counter + 1 == 4){
        counter = 1;
        }       
      else{
        counter = counter + 1;
        }      
    }


  //lighting leds

    if (counter == 1){
      digitalWrite(l3,LOW);
      digitalWrite(l2,LOW);
      digitalWrite(l1,HIGH);
      }
    if (counter == 2){
      digitalWrite(l1,LOW);
      digitalWrite(l3,LOW);
      digitalWrite(l2,HIGH);
      }
    if (counter == 3){
      digitalWrite(l1,LOW);
      digitalWrite(l2,LOW);
      digitalWrite(l3,HIGH);
      }

}