Online PHP editor | output for bH4Oh

<?php $str = 'a:1:{s:8:"post_tag";a:5:{i:460;a:5:{s:11:"wpseo_title";s:8:"demodemo";s:10:"wpseo_desc";s:8:"demodemo";s:13:"wpseo_bctitle";s:8:"demodemo";s:13:"wpseo_noindex";s:7:"default";s:21:"wpseo_sitemap_include";s:1:"-";}i:459;a:5:{s:11:"wpseo_title";s:8:"testtest";s:10:"wpseo_desc";s:8:"testtest";s:13:"wpseo_bctitle";s:8:"testtest";s:13:"wpseo_noindex";s:7:"default";s:21:"wpseo_sitemap_include";s:1:"-";}i:462;a:5:{s:11:"wpseo_title";s:7:"bikey77";s:10:"wpseo_desc";s:7:"bikey77";s:13:"wpseo_bctitle";s:7:"bikey77";s:13:"wpseo_noindex";s:7:"default";s:21:"wpseo_sitemap_include";s:1:"-";}i:463;a:5:{s:11:"wpseo_title";s:7:"dimitra";s:10:"wpseo_desc";s:7:"dimitra";s:13:"wpseo_bctitle";s:7:"dimitra";s:13:"wpseo_noindex";s:7:"default";s:21:"wpseo_sitemap_include";s:1:"-";}i:464;a:5:{s:11:"wpseo_title";s:8:"dimitra1";s:10:"wpseo_desc";s:8:"dimitra1";s:13:"wpseo_bctitle";s:8:"dimitra1";s:13:"wpseo_noindex";s:7:"default";s:21:"wpseo_sitemap_include";s:1:"-";}}}'; $data = unserialize($str); echo count($data['post_tag']);