const int l1 = 2;
const int l2 = 4;

int l1_state = 1;
int l2_state = 0;


void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);
  Serial.println("Hello, ESP32!");
  pinMode(l1, OUTPUT);
  pinMode(l2, OUTPUT);
  digitalWrite(l1, l1_state);
  digitalWrite(l2, l2_state);
}

void loop() {
  // put your main code here, to run repeatedly:
  // doc trang thai tai 2 chan
  l1_state = digitalRead(l1);
  l2_state = digitalRead(l2);

  digitalWrite(l1, !(l1_state));
  digitalWrite(l2, !(l2_state));

  delay(500);
  delay(10); // this speeds up the simulation
}