// C++ code
//
void setup()
{
  pinMode(4, OUTPUT);
  pinMode(3, OUTPUT);
}

void loop()
{
  digitalWrite(4,1);
  digitalWrite(3,0);
  delay(1000); // Wait for 1000 millisecond(s)
  digitalWrite(3,1);
    digitalWrite(4,0);
  delay(1000); // Wait for 1000 millisecond(s)
}

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