int red=7;
int yellow=12;
int green =13;
void setup() {
  pinMode(red, OUTPUT);
  pinMode(yellow, OUTPUT);
  pinMode(green, OUTPUT);
  // put your setup code here, to run once:

}

void loop() {
  digitalWrite(red,HIGH);
  digitalWrite(yellow,LOW);
  digitalWrite(green,LOW);
  delay(1500);
  digitalWrite(red,LOW);
  digitalWrite(yellow,HIGH);
  digitalWrite(green,LOW);
  delay(1500);
  digitalWrite(red,LOW);
  digitalWrite(yellow,LOW);
  digitalWrite(green,HIGH);
  delay(1500);

  // put your main code here, to run repeatedly:

}