How to Hide the "Video Sitemap" Admin Menu

function plt_hide_xml_sitemaps_for_videos_menus() {
	//Hide the "Tools → Video Sitemap" menu.
	remove_submenu_page('tools.php', 'video-sitemap-generate-page');
}

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

Where do I put this code?