int red = 1 ;
int yellow = 2;
int green = 3;

 void setup (){
   pinMode (red,OUTPUT);
   pinMode (yellow,OUTPUT);
   pinMode (green,OUTPUT);
   }

 void loop () {
 digitalWrite (red,HIGH);
 digitalWrite (yellow,LOW);
 digitalWrite (green,LOW);
 delay (5000);

 digitalWrite(red,LOW);
 digitalWrite(yellow,HIGH);
 digitalWrite(green,LOW);
 delay (2000);

 digitalWrite(red,LOW);
 digitalWrite(yellow,LOW);
 digitalWrite(green,HIGH);
 delay (5000);

 digitalWrite(red,LOW);
 digitalWrite(yellow,HIGH);
 digitalWrite(green,LOW);
 delay (2000);
 }