// C++ code
//
void setup()
{
  pinMode(16, OUTPUT);
  pinMode(17, OUTPUT);

  }

void loop()
{
  digitalWrite(16, HIGH);
  digitalWrite(17, LOW);
  
  delay(1000); // Wait for 1000 millisecond(s)
  digitalWrite(16,LOW);
  digitalWrite(17,HIGH);
  
  delay(1000);// Wait for 1000 millisecond(s) 
}