void setup(){
  pinMode(PC13,OUTPUT);
  pinMode(PC14,OUTPUT);
  pinMode(PC15,OUTPUT);
  
}
void loop(){
  digitalWrite(PC13,HIGH);
  digitalWrite(PC14,LOW);
  digitalWrite(PC15,LOW);
  delay(500);
  digitalWrite(PC13,LOW);
  digitalWrite(PC14,HIGH);
  digitalWrite(PC15,LOW);
  delay(500);
  digitalWrite(PC13,LOW);
  digitalWrite(PC14,LOW);
  digitalWrite(PC15,HIGH);
  delay(500);
}