void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);
  Serial.println("Hello, ESP32!");
  pinMode(15, OUTPUT);
  pinMode(2, INPUT_PULLUP);
}

void loop() {
  // put your main code here, to run repeatedly:
  delay(10);
  int a = digitalRead(2);
  digitalWrite(15,a); // this speeds up the simulation()
}