void setup() {
  Serial.begin(115200);   // set serial interface speed
  Serial.println ("setup");   // print each time setup runs
}

int cnt;      // variable of whole #s: 1, 2, 3

void loop() {
  Serial.print   ("loop: ");
  Serial.println (cnt);   // print each time loop runs
  cnt = cnt + 1;          // increment
  delay (500);            // 500 msec delay
}