How to Hide WP Auto Republish Admin Menus

function plt_hide_wp_auto_republish_menus() {
	//Hide "Auto Republish".
	remove_menu_page('wp-auto-republish');
	//Hide "Auto Republish → WP Auto Republish".
	remove_submenu_page('wp-auto-republish', 'wp-auto-republish');
	//Hide "Auto Republish → Contact Us".
	remove_submenu_page('wp-auto-republish', 'wp-auto-republish-contact');
	//Hide "Auto Republish → Upgrade".
	remove_submenu_page('wp-auto-republish', 'wp-auto-republish-pricing');
}

add_action('admin_menu', 'plt_hide_wp_auto_republish_menus', 1000000000);

Where do I put this code?