#define LED 2 
int NO;
void setup() {
  Serial.begin(9600);
 pinMode(2, OUTPUT);
}
void loop() {
    
    Serial.println("NO = 0");
    delay(1000);
 Serial.println("NO = 1");
    delay(1000);
 Serial.println("NO = 2");
    delay(1000);
 Serial.println("NO = 3");
    delay(1000);
 
}