20
..........ox......x.
......o............x
....x....x.x........
........oo......x..o
............x.x.x...
..x...o.............
..............xx....
..........xo..xx....
....o.....o....o.xox
...o.oo....ox.....o.
..o.......xxo..o....
....xx...ox.o.oo....
.......o.....x...o.x
...x..o..x..x..x.x.x
.........o..x.x.....
..xoxoo...........x.
..o...o....x.o....o.
.........x..o...x...
o..o..o.o...........
......o.............
