% slitherlink 423 by Otto Janko, http://www.janko.at/Raetsel/Slitherlink/423.a.htm
slitherlink
medium-
10 10
22.2...33.
.23.31.1.3
...2....3.
..1.3.121.
1..111....
..2.....21
12.23.23.3
.....2.12.
.2.2.23..1
.333..2...
