void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);
  Serial.println("Hello, ESP32!");
  pinMode(12,OUTPUT);
  pinMode(21,OUTPUT);
  pinMode(19,OUTPUT);
  pinMode(26, INPUT);
}

void loop() {
  int a=digitalRead(26);
  if(a==1){
  Serial.println(a);  
  digitalWrite(12, HIGH);
  delay(2000);
  digitalWrite(12, LOW);
  digitalWrite(21, HIGH);
  delay(2000);
  digitalWrite(21, LOW);
  digitalWrite(19, HIGH);
  delay(2000);
  digitalWrite(19, LOW);
  }
  else(a==0);{
    digitalWrite(12, LOW);
    digitalWrite(21, LOW);
    digitalWrite(19, LOW);
    Serial.println(a);
  }
}