#define LED1 4  // Pin for LED 1
#define LED2 5  // Pin for LED 2

void setup() {
  pinMode(LED1, OUTPUT); // Set LED1 pin as output
  pinMode(LED2, OUTPUT); // Set LED2 pin as output
}

void loop() {
  digitalWrite(LED1, HIGH); // Turn LED1 ON
  digitalWrite(LED2, LOW);  // Turn LED2 OFF
  delay(1000);              // Wait for 1 second

  digitalWrite(LED1, LOW);  // Turn LED1 OFF
  digitalWrite(LED2, HIGH); // Turn LED2 ON
  delay(1000);              // Wait for 1 second
}