% slitherlink 421 by Otto Janko, http://www.janko.at/Raetsel/Slitherlink/421.a.htm
slitherlink
medium-
10 10
....3.32.3
2..2112.2.
321..2.2.3
.22..12.12
3..1.2..22
..3122.203
.2.222..2.
.1..2...1.
..3231123.
.23....3.3
