long ms;
bool press;
long num;

void setup() {
  // put your setup code here, to run once:
  pinMode(A0, INPUT_PULLUP);

  Serial.begin(115200);
}

void loop() {
  // put your main code here, to run repeatedly:
  if (!analogRead(A0))
  {
    ms = millis() + 100;

    while (!analogRead(A0))
    {
      if (ms <= millis())
      {
        press = true;
      }
      else
      {
        press = false;
      }
    }
  }

  if (press)
  {
    num++;
    Serial.println(num);
  }
}