int red = 9;
int yellow = 8;
int green = 7;

void setup(){

  pinMode(red, OUTPUT);
  pinMode(yellow, OUTPUT);
  pinMode(green, OUTPUT);

}
void loop(){
  digitalWrite(red, HIGH);
  delay(15000);
  digitalWrite(red, LOW);

  digitalWrite(yellow, HIGH);
  delay(1000);
  digitalWrite(yellow, LOW);
  delay(500);

  digitalWrite(green, HIGH);
  delay(20000);
  digitalWrite(green, LOW);

  digitalWrite(yellow, HIGH);
  delay(1000);
  digitalWrite(yellow, LOW);
  delay(500);
}