# Back end code
- code     ```php    ", "", $notetoadd);        $notetoadd = str_replace("    ```# Solution
notice that input is filtered 3 times, now to escape that filter we need to nest filtered commands, like so:
```php <<< cacacacattttflag  --> flaflaflaflagggg```
as you can see i nested the commands four times so that after all the filtering is done we're left with the original command we intended
and the final payload:
```php<<<>>>```
`flag{wait_but_i_fixed_it_after_my_last_two_blunders_i_even_filtered_three_times_:(((}`