20
x..x....o......x..o.
..xox...........ox..
............x...x...
....o....oo.........
xx.....x.......xx.x.
...x..x.x..........o
...xox....o.o...ox..
....................
...ox...oo......x.o.
..........o...o.....
..x................o
o......o..o..o......
..........xoo.x.....
......o..x...o....x.
xox....x.......x.x..
x..........o......o.
...x......x..x...o..
o.....o.....xo.....x
x.o.......o...o....x
...o.......o.....o..
