How to Hide the "ImageMagick Engine" Admin Menu

function plt_hide_imagemagick_engine_menus() {
	//Hide the "Settings → ImageMagick Engine" menu.
	remove_submenu_page('options-general.php', 'imagemagick-engine');
}

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

Where do I put this code?