const int button = 5;
const int led = 21;
int button_state = 0;
int lastButtonState = LOW;
int ledState = LOW;

void setup() {
  Serial.begin(115200);
  Serial.println("Hello, ESP32");
  pinMode(button, INPUT);
  pinMode(led, OUTPUT);
}

void loop() {
  button_state = digitalRead(button);
  Serial.println(button_state);

  if (button_state == HIGH && lastButtonState == LOW) {
    if (ledState == LOW) {
      ledState = HIGH; 
    } else {
      ledState = LOW; 
    }
    digitalWrite(led, ledState);
  }

  lastButtonState = button_state;
  delay(10);
}