int LEDROJO = 19;
int LEDAMARILLO = 18;
int LEDVERDE = 16;

void setup() { 
  pinMode(LEDROJO, OUTPUT);
  pinMode(LEDAMARILLO, OUTPUT);
  pinMode(LEDVERDE, OUTPUT);
} 

void loop() {
  digitalWrite(LEDROJO, HIGH);
  delay(1000);
  digitalWrite(LEDROJO, LOW);
  delay(1000);

  digitalWrite(LEDAMARILLO, HIGH);
  delay(1000);
  digitalWrite(LEDAMARILLO, LOW);
  delay(1000);

  digitalWrite(LEDVERDE, HIGH);
  delay(1000); 
  digitalWrite(LEDVERDE, LOW);
  delay(1000);
}