bool recent_status;
bool current_status;
void setup() {
  // put your setup code here, to run once:
  pinMode(16, INPUT_PULLUP);
  pinMode(18, OUTPUT);

  Serial.begin(9600);
}

void loop() {
  current_status = digitalRead(16);
  if (current_status == LOW && recent_status == HIGH) {
    recent_status = LOW;
    Serial.println("1");
    delay(10);
  }
  if (current_status == HIGH && recent_status == LOW) {
    recent_status = HIGH;
    Serial.println("2");
    delay(10);
  }
}