int redLight = 3;
int yellowLight = 4;
int greenLight = 5;

void setup() {
  
  pinMode(redLight, OUTPUT);
  pinMode(yellowLight, OUTPUT);
  pinMode(greenLight, OUTPUT);
}

void loop() {
  
  digitalWrite(redLight, HIGH);  
  delay(5000);                     
  digitalWrite(redLight, LOW);  
  
  
  digitalWrite(yellowLight, HIGH); 
  delay(2000);                     
  digitalWrite(yellowLight, LOW); 

  
  digitalWrite(greenLight, HIGH);   
  delay(5000);                     
  digitalWrite(greenLight, LOW);    
}