How to Hide EZ Horoscope Admin Menus

function plt_hide_ez_horoscope_menus() {
	//Hide the "Settings → Horoscope Settings" menu.
	remove_submenu_page('options-general.php', 'ez-horoscope-settings');
	//Hide the "Settings → Contact Us" menu.
	remove_submenu_page('options-general.php', 'ez-horoscope-settings-contact');
	//Hide the "Settings → Upgrade" menu.
	remove_submenu_page('options-general.php', 'ez-horoscope-settings-pricing');
}

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

Where do I put this code?