private static void Swap(this byDate f, long i, long j)
{
f[i] = f[j];
f[j] = f[i];
}
private static bool Less(this byDate f, long i, long j)
{
return(f[i].date < f[j].date);
}
private static long Len(this byDate f)
{
return(len(f));
}