How to Hide the "Click to top" Admin Menu

function plt_hide_click_to_top_menus() {
	//Hide the "Settings → Click to top" menu.
	remove_submenu_page('options-general.php', 'click-to-top.php');
}

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

Where do I put this code?