functionremoveStr($str){
$pat='/816/';
$res=preg_replace($pat,'',$str);
returnpreg_match($pat,$res)?removeStr($res):$res;
}
                            

functionglops($str)
{
$l=strlen($str);
while($l>=3){
$pos=strpos($str,'816');
if($pos||$pos===0){
$str=substr_replace($str,"",$pos,3);
}else{
break;
}
}
return$str;
}