int ledPin = 13;

void setup() {
  pinMode(ledPin,OUTPUT );
  Serial.begin(9600);

  Serial.println("=== Countdown beginning ===");

  int counter = 5; // start the counter at 5

  while (counter>0){// KEEP LOOPING while counter is greater than 0
  Serial.print("Counter is: ");
  Serial.println(counter);

  delay(1000);     //wait 1 second between numbers
  counter = counter - 1;  // VERY IMPORTANT :decrease counter each time
  }
Serial.println("liftoff!");

//Flash the LED 3 times to celebrate
digitalWrite (ledPin, HIGH);  delay(200); digitalWrite(ledPin, LOW); delay(200);
digitalWrite (ledPin, HIGH);  delay(200); digitalWrite(ledPin, LOW); delay(200);
digitalWrite (ledPin, HIGH);  delay(200); digitalWrite(ledPin, LOW); delay(200);
}

void loop() {


}