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

void setup() {

  Serial.begin(9600);
  pinMode(13, OUTPUT);
  pinMode(8, INPUT_PULLUP);
  buducnost = millis() + 500;
}

void loop() {

if(millis() > buducnost)

{
  if(digitalRead(13) == LOW)
  {
    digitalWrite(13, HIGH);
  }
  else
  {
    digitalWrite(13, LOW);
  }
 buducnost = millis() + 500;
}

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



}