#define RED 1
#define YELLOW 4
#define GREEN 10

void setup() {
  pinMode(RED, OUTPUT);
  pinMode(YELLOW, OUTPUT);
  pinMode(GREEN, OUTPUT);
}

void loop() {
  digitalWrite(RED, HIGH);
  digitalWrite(GREEN,LOW);
  digitalWrite(YELLOW,LOW);
  delay(20000);

  digitalWrite(RED, LOW);
  digitalWrite(GREEN, HIGH);
  digitalWrite(YELLOW,LOW);
  delay(10000);

  digitalWrite(RED, LOW);
  digitalWrite(GREEN,LOW);
  digitalWrite(YELLOW, HIGH);
  delay(2000);
}