% nurikabe 173 by ooya, http://www.janko.at/Raetsel/Nurikabe/173.a.htm
nurikabe
medium-
18 10
..2....5...5..4...
....4........5....
.....2..4......4..
..................
............4.....
..5....5..........
...5....5.........
.............4..5.
.................5
.4.........4......
