# -*- coding: utf-8 -*-
s = gets
s =~ /(?<=<a href=").*?(?=">)/
p $&
IyAtKi0gY29kaW5nOiB1dGYtOCAtKi0KcyA9IGdldHMKcyA9fiAvKD88PTxhIGhyZWY9IikuKj8oPz0iPikvCnAgJCY=
Jmx0O2EgaHJlZj0mcXVvdDtodHRwOi8vaC4uLmNvbnRlbnQtYXZhaWxhYmxlLXRvLWF1dGhvci1vbmx5Li4uZS5jb20mcXVvdDsmZ3Q744GuaG9nZWhvZ2UuY29t44Gg44GR5q2j6KaP6KGo54++44Gn5oqc44GN5Ye644GX44Gf44GE44KT44Gg44GR44Gp
<a href="http://h...content-available-to-author-only...e.com">のhogehoge.comだけ正規表現で抜き出したいんだけど