int btn = 19, btn2 = 5, led = 27, led2 = 14, led3 = 12, poten = 0;
int counter = 0;

void setup() {
  Serial.begin(115200);
  pinMode(btn, INPUT_PULLUP);
  pinMode(btn2, INPUT_PULLUP);
  pinMode(led, OUTPUT);
  pinMode(led2, OUTPUT);
  pinMode(led3, OUTPUT);
  pinMode(poten, INPUT);
}

void loop() {

  int potenValue = analogRead(poten);
   Serial.println(counter);

  int btnValue = digitalRead(btn);
  if (btnValue == 0) {
    while (digitalRead(btn) == 0) {}
    counter = counter - 1;
    if (counter < 0 ) {
      counter = 0;
    }
  }
  int btn2Value = digitalRead(btn2);
  if (btn2Value == 0) {
    while (digitalRead(btn2) == 0) {}
    counter = counter + 1;
    if (counter > 3) {
      counter = 3;
    }
  }
  int mappedValue = map(potenValue, 0, 4095, 0, 255);
  if (counter == 1) {
    analogWrite(led, mappedValue);
    analogWrite(led2, 0);
    analogWrite(led3, 0);
  }
    if (counter == 2) {
    analogWrite(led, mappedValue);
    analogWrite(led2, mappedValue);
    analogWrite(led3, 0);
  }
    if (counter == 3) {
    analogWrite(led, mappedValue);
    analogWrite(led2, mappedValue);
    analogWrite(led3, mappedValue);
  }
  if (counter >= 0 ) {
    analogWrite(led, 0);
    analogWrite(led2, 0);
    analogWrite(led3, 0);
  }
  delay(100);
}