const int LED1 = 2;
const int LED2 = 4;
const int S1 = 13;


void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);
  Serial.println("Hello, ESP32!");
  pinMode(LED1, OUTPUT);
  pinMode(LED2, OUTPUT);
  pinMode(S1, INPUT_PULLUP);
}

void loop() {
  // put your main code here, to run repeatedly:
  if (digitalRead(S1)== LOW)
    digitalWrite(LED2, HIGH);
  else
    digitalWrite(LED2, LOW);
  digitalWrite(LED1, HIGH);
  delay(500); // this speeds up the simulation
  digitalWrite(LED1, LOW);
  delay(500);
}