How to Hide Directly Import Admin Menus

function plt_hide_directly_import_menus() {
	//Hide the "Tools → Directly Import" menu.
	remove_submenu_page('tools.php', 'directly_import_sites');
	//Hide the "Settings → Directly Import" menu.
	remove_submenu_page('options-general.php', 'directly_import_settings');
}

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

Where do I put this code?