How to Hide WP iCal Availability Free Admin Menus

function plt_hide_wp_ical_availability_menus() {
	//Hide the "WP iCal Availability" menu.
	remove_menu_page('wp-ical-availability');
	//Hide the "WP iCal Availability → Calendars" menu.
	remove_submenu_page('wp-ical-availability', 'wp-ical-availability');
	//Hide the "WP iCal Availability → Settings" menu.
	remove_submenu_page('wp-ical-availability', 'wp-ical-availability-settings');
}

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

Where do I put this code?