How to Hide Comment Reply Email Notification Admin Menus

function plt_hide_comment_reply_email_notification_menus() {
	//Hide the "Settings → Comment Reply Email Notification" menu.
	remove_submenu_page('options-general.php', 'comment_reply_email_notification');

	//Hide the "Comments → All Comments" menu.
	remove_submenu_page('edit-comments.php', 'edit-comments.php');
	//Hide the "Comments → Comment subscriptions" menu.
	remove_submenu_page('edit-comments.php', 'comment_reply_email_notification_subscriptions');
}

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

Where do I put this code?