const int lad1 = 7;
const int lad2 = 6;
const int lad3 = 5;
const int lad4 = 4;
const int lad5 = 3;

void setup() 
{ 
pinMode(lad1 , OUTPUT);
pinMode(lad2 , OUTPUT);
pinMode(lad3 , OUTPUT);
pinMode(lad4 , OUTPUT);
pinMode(lad5 , OUTPUT);

}

void loop() 
{
  digitalWrite(lad1, HIGH);
  digitalWrite(lad1, LOW);
  delay(300);
  digitalWrite(lad2, HIGH);
  digitalWrite(lad2, LOW);
  delay(300);
  digitalWrite(lad3, HIGH);
  digitalWrite(lad3, LOW);
  delay(300);
  digitalWrite(lad4, HIGH);
  digitalWrite(lad4, LOW);
  delay(300);
  digitalWrite(lad5, HIGH);
  digitalWrite(lad5, LOW);
  delay(300);
  // put your main code here, to run repeatedly:

}