int binsearch (int x)
{
  int a[16];
  signed low = 0, high = 16;
 
  while (low < high)
  {
    signed middle = low + ((high - low) >> 1);
    
    if (a[middle]<x)
      high = middle;
    else if (a [middle] > x)
      low = middle + 1;
    else /* a [middle] == x ! */
      return middle;
  }
 return -1;
}


int buf[4];
int hi = 0;
int lo = 0;
int size = 4;

void enqueue (int x)
{
  buf [hi] = x;
  hi = (hi + 1);
}


int dequeue ()
{
  int res = buf [lo];
  lo = (lo + 1);
  return res;
}

void queue_test (void)
{
  while (nondet_int ())
    {
      if (nondet_int ())
	{
	  int x = nondet_int ();
	  enqueue (x);
	}
      else
	dequeue ();
    }
}