#define RED_PIN 8
#define YELLOW_PIN 9
#define GREEN_PIN 10

void setup() {
  pinMode(RED_PIN, OUTPUT);
  pinMode(YELLOW_PIN, OUTPUT);
  pinMode(GREEN_PIN, OUTPUT);
}

void loop() {
  digitalWrite(RED_PIN, HIGH);    // Turn on RED
  digitalWrite(YELLOW_PIN, LOW);  // Turn off YELLOW
  digitalWrite(GREEN_PIN, LOW);   // Turn off GREEN
  delay(30000);                   // Wait for 30 seconds

  digitalWrite(RED_PIN, LOW);     // Turn off RED
  digitalWrite(YELLOW_PIN, HIGH); // Turn on YELLOW
  digitalWrite(GREEN_PIN, LOW);   // Turn off GREEN
  delay(5000);                    // Wait for 5 seconds

  digitalWrite(RED_PIN, LOW);     // Turn off RED
  digitalWrite(YELLOW_PIN, LOW);  // Turn off YELLOW
  digitalWrite(GREEN_PIN, HIGH);  // Turn on GREEN
  delay(25000);                   // Wait for 25 seconds
}