How to Hide the "Better Search Replace" Admin Menu

function plt_hide_better_search_replace_menus() {
	//Hide the "Tools → Better Search Replace" menu.
	remove_submenu_page('tools.php', 'better-search-replace');
}

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

Where do I put this code?