How to Hide the "Auto Update Post Date" Admin Menu

function plt_hide_auto_update_post_date_menus() {
	//Hide the "Tools → Auto Update Post Date" menu.
	remove_submenu_page('tools.php', 'tmaupd-settings');
}

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

Where do I put this code?