Warning: include(function.php): failed to open stream: No such file or directory in /index.php on line 2

Warning: include(function.php): failed to open stream: No such file or directory in /index.php on line 2

Warning: include(): Failed opening 'function.php' for inclusion (include_path='.:/:/usr/local/php56/lib/pear') in /index.php on line 2

Fatal error: Call to undefined function zlicz() in /index.php on line 5