% slitherlink 171 by Otto Janko, http://www.janko.at/Raetsel/Slitherlink/171.a.htm
slitherlink
hard-
20 15
2232332..2...1.....3
232.22..11.1.2...1..
...12..32.22...132..
.22....2.22.1221.2..
.2...2.00123...2....
.1212.3..22.1....31.
22..22.3.3.3.333.23.
2.2...2..2.3..1.0.21
...32..31......20.2.
3...2...2...3.....13
..3..32.22.23.......
....2..21...2.2.23..
.332..2..30..3.3...3
222.3..3.....12.2...
.....3...21.3.212.2.
