// Define the LED pins and button pin
const int RED_LED_PIN = 9;
const int GREEN_LED_PIN = 10;
const int BUTTON_PIN = 2;

void setup() {
  // Set LED pins as output
  pinMode(RED_LED_PIN, OUTPUT);
  pinMode(GREEN_LED_PIN, OUTPUT);

  // Set button pin as input with pull-up resistor
  pinMode(BUTTON_PIN, INPUT_PULLUP);
}

void loop() {
  // Read button state
  int buttonState = digitalRead(BUTTON_PIN);

  if (buttonState == LOW) {
    // Button is pressed, turn on green LED and turn off red LED
    digitalWrite(GREEN_LED_PIN, LOW);
    digitalWrite(RED_LED_PIN, HIGH);
  } else {
    // Button is not pressed, turn on red LED and turn off green LED
    digitalWrite(RED_LED_PIN, LOW);
    digitalWrite(GREEN_LED_PIN, HIGH);
  }

  // Wait a short time to debounce the button
  delay(50);
}