#define button 2
int cnt = 0;
bool state = 0;
int last_state = 0;
void setup() {
  Serial.begin(115200);
  pinMode(button, INPUT); //configure to input mode
}

void loop() {
  state = !digitalRead(button);
  if(state != last_state){
    if(state == 0){
      cnt += state;
      Serial.println(cnt);
    }
    delay(40);
  }
  last_state = state;
}