void setup() {
  pinMode(9, OUTPUT);
  pinMode(8, OUTPUT); 
  pinMode(7, OUTPUT);
  Serial.begin(9600); 
}

void loop() {
  for (int green = 15; green >= 0; green--) {
    digitalWrite(9, LOW);   
    digitalWrite(8, LOW);   
    digitalWrite(7, HIGH);  
    Serial.print("Green time left: ");
    Serial.print(green);
    Serial.println(" seconds");
    delay(1000); 
  }

  for (int yellow = 5; yellow >= 0; yellow--) {
    digitalWrite(9, LOW);   
    digitalWrite(8, HIGH);  
    digitalWrite(7, LOW);   
    Serial.print("Yellow time left: ");
    Serial.print(yellow);
    Serial.println(" seconds");
    delay(1000);
  }

  for (int red = 10; red >= 0; red--) {
    digitalWrite(9, HIGH);  
    digitalWrite(8, LOW);   
    digitalWrite(7, LOW);   
    Serial.print("Red time left: ");
    Serial.print(red);
    Serial.println(" seconds");
    delay(1000); 
  }
}