#define LED_PIN PC13
#define BUTTON_PIN PA0

void setup() {
  pinMode(LED_PIN, OUTPUT);
  pinMode(BUTTON_PIN, INPUT_PULLUP); // Internal pull-up resistor
}

void loop() {
  int buttonState = digitalRead(BUTTON_PIN);

  if (buttonState == LOW) { // Button pressed
    digitalWrite(LED_PIN, LOW); // ON (active low LED)
  } else { // Button not pressed
    digitalWrite(LED_PIN, HIGH); // OFF
  }
}