How to Hide Media Library Folders Admin Menus

function plt_hide_media_library_plus_menus() {
	//Hide "Media Library Folders".
	remove_menu_page('mlf-folders8');
	//Hide "Media Library Folders → Folders  Files".
	remove_submenu_page('mlf-folders8', 'mlf-folders8');
	//Hide "Media Library Folders → Thumbnails".
	remove_submenu_page('mlf-folders8', 'mlf-thumbnails');
	//Hide "Media Library Folders → Image SEO".
	remove_submenu_page('mlf-folders8', 'mlf-image-seo');
	//Hide "Media Library Folders → Settings".
	remove_submenu_page('mlf-folders8', 'mlf-settings8');
	//Hide "Media Library Folders → Support".
	remove_submenu_page('mlf-folders8', 'mlf-support8');
	//Hide "Media Library Folders → Upgrade to Pro".
	remove_submenu_page('mlf-folders8', 'mlp-upgrade-to-pro');
}

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

Where do I put this code?