int ledamarillo = 2;
int ledrojo = 5;

void setup() {
  pinMode(ledamarillo, OUTPUT);
  pinMode(ledrojo, OUTPUT);
}

void loop() {
  while(1){
 digitalWrite(ledamarillo, HIGH);
 digitalWrite(ledrojo, HIGH);
 delay(1000);
 digitalWrite(ledamarillo, LOW);
 digitalWrite(ledrojo, LOW);
 delay(1000);
}
}