#define BTN_PIN 4
#define LED_PIN 2

int lastButtonState;
int ledState;

void setup() {
  Serial.begin(115200);
  Serial.println("Hello, ESP32!");

  pinMode(BTN_PIN, INPUT_PULLUP);
  pinMode(LED_PIN, OUTPUT);

  lastButtonState = HIGH;
  ledState = HIGH;
  digitalWrite(LED_PIN, ledState);
}

void loop() {
  int currentButtonState = digitalRead(BTN_PIN);
  
  if (currentButtonState == LOW && lastButtonState == HIGH) {
    ledState = !ledState;
    digitalWrite(LED_PIN, ledState);
  }

  lastButtonState = currentButtonState;

  delay(10);
}