20
oo....oox.....o..x.x
...x........x.o.....
..o.....x...x.......
.....o....xo.x.x....
........x.........o.
o.......o........o.o
x...x...o..xo...o...
...o................
.x.o.o.........x....
.....xx.x....x.x....
x.o...oo.x......o...
...........xo..o....
.....o.o.....oo.x..x
.........xxx......x.
........o......o....
.......x.x..........
.......o.x..........
....ox........o...x.
...o..o.............
...x.xoxxo.xo.......
