How to Hide Firelight Lightbox Admin Menus

function plt_hide_easy_fancybox_menus() {
	//Hide the "Lightbox" menu.
	remove_menu_page('firelight-settings');
	//Hide the "Lightbox → Settings" menu.
	remove_submenu_page('firelight-settings', 'firelight-settings');
	//Hide the "Lightbox → Go Pro" menu.
	remove_submenu_page('firelight-settings', 'firelight-pro');
}

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

Where do I put this code?