20
..............xxo...
....o.o.....o.......
ooo.......x......xx.
......x..ox..x.....o
..x.x...o....ooo....
..x.x.x............o
...x......o.........
.o...o.o.o..........
....xxx..o.x.....o..
.......x..x.....xx..
....x.o......o...o..
......o...o.ooo.....
..x..........x.xx.x.
o......o....x.....x.
....x.............o.
.x..x.o.o.........o.
......x..o.........x
.........x..o..o.xo.
.......x..ox......x.
....................
