#define outputA 2
#define outputB 3
#define buttonPin 8

int counter = 0;
int aState;
int aLastState;
int buttonState;
int lastButtonState;

void setup() {
  // put your setup code here, to run once:
  pinMode(outputA, INPUT);
  pinMode(outputB, INPUT);
  pinMode(buttonPin, INPUT_PULLUP);

  Serial.begin(9600);
  aLastState = digitalRead(outputA);

}

void loop() {
  // put your main code here, to run repeatedly:

  buttonState = digitalRead(buttonPin);

  aState = digitalRead(outputA);

  if (aState != aLastState) {
    if(digitalRead(outputB) != aState) {
      counter++;
    } else {
      counter--;
    }
    Serial.print("Position: ");
    Serial.println(counter);
  }

  if (!buttonState && buttonState != lastButtonState) {
    counter /= 2;
    Serial.print("Position: ");
    Serial.println(counter);
  }


  lastButtonState = buttonState;
  aLastState = aState;
}