How to Hide WP RSS Aggregator Admin Menus

function plt_hide_wp_rss_aggregator_menus() {
	//Hide the "Feed Items" menu.
	remove_menu_page('edit.php?post_type=wprss_feed_item');
	//Hide the "Aggregator" menu.
	remove_menu_page('aggregator');
}

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

Where do I put this code?