preg_replace: replace everything but

I want to remove some unwanted characters from the following string. Here's the code.

 $input="aecąßÄ1,.!?-_'\"/><";  
    $input=preg_replace('/[^\p{P}\p{L}\p{N}\s]*/u', '', $input); 

The code seems to be working fine but the special characters are lost in the output. Here's what 开发者_运维知识库I get.

   aec���1,.!?-_'"/  

Instead of

 aecąßÄ1,.!?-_'"/  

Why is it so?

EDIT based on comment:

Try to use "real" characters:

$input=  preg_replace('/[^aecąßÄ1,.!?-_\'\"\/]/', '', $input);

last answer:

If you want to remove unwanted characters, you can remove that characters with much simpler regex:

$input= "aecąßÄ1,.!?-_'\"/><";
$input=  preg_replace('/[<>]/', '', $input);

Just put that special characters between [ ] in regex. This will works in your case.