void setup() 
{
  for (int k = 13 ; k >= 4 ; k--)
  {
    pinMode(k, OUTPUT);
  }
  pinMode(A0, INPUT_PULLUP);
  pinMode(A1, INPUT_PULLUP);
 }
void loop() 
{
  bool down = digitalRead(A1);
  if (down == 0)
  {
    for (int k = 13 ; k >= 4 ; k--)
    {
      digitalWrite(k , HIGH);
      delay(100);
      digitalWrite(k , LOW);
      delay(100);
    }
  }
  bool up = digitalRead(A0);
  if (up == 0)
  {
    for (int k = 4 ; k <= 13 ; k++)
    {
      digitalWrite(k , HIGH);
      delay(100);
      digitalWrite(k , LOW);
      delay(100);
    }  
  }
}