void setup() {
 
  pinMode(13, INPUT_PULLUP);
  pinMode(12, INPUT_PULLUP);

  pinMode(15, OUTPUT);
  pinMode(4, OUTPUT);
  pinMode(5, OUTPUT);
  pinMode(18, OUTPUT);

}


void loop() {
 
digitalWrite(15, HIGH);delay(500);
digitalWrite(15, LOW);delay(500);
digitalWrite(4, HIGH);delay(500);
digitalWrite(4,LOW);delay(500);
digitalWrite(5, HIGH);delay(500);
digitalWrite(5, LOW);delay(500);
digitalWrite(18, HIGH); delay(500);
digitalWrite(18, LOW); delay(500);



}