int led1 = 0;
int led2 = 1; 
int led3 = 2;
int led4 = 3;
int led5 = 4;
void setup(){
  pinMode (led1, OUTPUT);
  pinMode (led2, OUTPUT);
  pinMode (led3, OUTPUT);
  pinMode (led4, OUTPUT);
  pinMode (led5, OUTPUT);
}
void loop (){
  digitalWrite (led1, HIGH); 
  delay(50);
  digitalWrite (led1, LOW );
  digitalWrite (led2, HIGH);
  delay(50);
  digitalWrite (led2, LOW);
  digitalWrite (led3, HIGH);
  delay(50);
  digitalWrite (led3, LOW);
  digitalWrite (led4, HIGH);
  delay(50);
  digitalWrite (led4, LOW);
  digitalWrite (led5, HIGH);
  delay(50);
  digitalWrite (led5, LOW);
  delay(1000);
   
  
  
  
  
}