const int buttonPin = 26;

int state = 0;

void setup() {
  Serial.begin(115200);
  Serial.println("121000672-Nguyễn Trần Giang Vỹ - 21CT113");
  pinMode(buttonPin, INPUT);
}

void loop() {
  state = digitalRead(buttonPin);
  if(state == HIGH)
  {
    Serial.println("Rảnh");
  }
  
  else
  {
    Serial.println("Bận");
  }
}