int cislo = 0;
unsigned long int buducnost;
bool test = true;

void setup() {
 pinMode(7, OUTPUT);
 Serial.begin(9600);
 pinMode(8, INPUT_PULLUP);

}

void loop() {
  if(millis() > buducnost)
  {
    if(digitalRead(7) == LOW)
    {
      digitalWrite(7, HIGH);
    }
    else
    {
      digitalWrite(7, LOW);
    }

    buducnost = millis() + 500;
  }

  if(digitalRead(8) == LOW && test == true)
  {
    cislo++;
    test == false;
    Serial.println(cislo);
  }
  else if(digitalRead(8) == HIGH && test == false)
  {
    test == true;
  }

  
}