How to Hide the "User Submitted Posts" Admin Menu

function plt_hide_user_submitted_posts_menus() {
	//Hide the "Settings → User Submitted Posts" menu.
	remove_submenu_page('options-general.php', 'user-submitted-posts/user-submitted-posts.php');
}

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

Where do I put this code?