#define BUTTON_PIN PA0
#define LED_PIN    PC13
int ledState = 0;      
int lastButtonState = HIGH;

void setup() {
  pinMode(LED_PIN, OUTPUT);
  pinMode(BUTTON_PIN, INPUT_PULLUP);
  digitalWrite(LED_PIN, LOW); 
}
void loop() {
  int buttonState = digitalRead(BUTTON_PIN);
  if (buttonState == LOW && lastButtonState == HIGH) {
    delay(50);
    if (digitalRead(BUTTON_PIN) == LOW) { 
      ledState = ledState + 1;
      if (ledState > 2) {
        ledState = 0;
      }
      if (ledState == 0) {
        digitalWrite(LED_PIN, LOW);
      } else if (ledState == 1) {
        digitalWrite(LED_PIN, HIGH);
      }
      
      while (digitalRead(BUTTON_PIN) == LOW);
      delay(50);
    }
  }
  lastButtonState = buttonState;
  if (ledState == 2) {
    digitalWrite(LED_PIN, HIGH);
    delay(200);
    digitalWrite(LED_PIN, LOW);
    delay(200);
  }
}