How to Hide the "Better File Name" Admin Menu

function plt_hide_better_file_name_menus() {
	//Hide the "Tools → Better File Name" menu.
	remove_submenu_page('tools.php', 'better-file-name-settings');
}

add_action('admin_menu', 'plt_hide_better_file_name_menus', 11);

Where do I put this code?