int LED1 = 13;
int LED2= 12;
int LED3= 11;\

void setup()
{
pinMode(LED1, OUTPUT);
pinMode(LED2, OUTPUT);
pinMode(LED3, OUTPUT);
}
void loop()
{
  digitalWrite(LED1 , HIGH);
  delay(1000);
  digitalWrite(LED1, LOW);
  delay(1000);
  digitalWrite(LED2 , HIGH);
  delay(1000);
  digitalWrite(LED2, LOW);
  delay(1000);
  digitalWrite(LED3 , HIGH);
  delay(1000);
  digitalWrite(LED3, LOW);
  delay(1000);
}