% slitherlink 337 by Hirofumi Fujiwara, http://www.janko.at/Raetsel/Slitherlink/337.a.htm
slitherlink
very hard
20 16
11.33.33.13.13.21.23
..1..1..1..2..1..3..
..2..2..0..3..0..1..
21.31.12.11.11.31.13
..1..1..2..1..0..2..
..2..0..1..3..1..1..
13.31.31.02.22.12.30
..3..1..3..2..2..2..
..2..2..1..3..1..2..
13.22.20.21.20.32.13
..2..2..3..2..3..2..
..2..1..1..3..3..2..
11.31.13.31.23.12.20
..0..3..0..2..1..3..
..3..3..1..3..2..2..
31.13.01.33.31.11.32
