function myFormat($yournum)
{
        if (strlen($yournum)==0)
        {
            return '';
        }
        elseif (strlen($yournum)==3)
        {
            return $yournum;
        }
        elseif (strlen($yournum)==2)
        {
            return '0'.$yournum;
         }
        else
        {
            return '00'.$yournum;
         }
}