How to Hide Automatic YouTube Gallery Admin Menus

function plt_hide_automatic_youtube_gallery_menus() {
	//Hide "YouTube Gallery".
	remove_menu_page('automatic-youtube-gallery');
	//Hide "YouTube Gallery → Dashboard".
	remove_submenu_page('automatic-youtube-gallery', 'automatic-youtube-gallery');
	//Hide "YouTube Gallery → Settings".
	remove_submenu_page('automatic-youtube-gallery', 'automatic-youtube-gallery-settings');
	//Hide "YouTube Gallery → Contact Us".
	remove_submenu_page('automatic-youtube-gallery', 'automatic-youtube-gallery-contact');
	//Hide "YouTube Gallery → Support Forum".
	remove_submenu_page('automatic-youtube-gallery', 'automatic-youtube-gallery-wp-support-forum');
	//Hide "YouTube Gallery → Upgrade".
	remove_submenu_page('automatic-youtube-gallery', 'automatic-youtube-gallery-pricing');
}

add_action('admin_menu', 'plt_hide_automatic_youtube_gallery_menus', 1000000000);
Where do I put this code?