void setup() {
  pinMode(2, OUTPUT); // Set pin 2 as output
  pinMode(3, OUTPUT); // Set pin 3 as output
}

void loop() {
  digitalWrite(2, HIGH); // Turn on LED connected to pin 2
  digitalWrite(3, LOW);  // Turn off LED connected to pin 3
  delay(500);            // Wait for 500 milliseconds
  digitalWrite(2, LOW);  // Turn off LED connected to pin 2
  digitalWrite(3, HIGH); // Turn on LED connected to pin 3
  delay(500);            // Wait for 500 milliseconds
}