20
o.......x.o..xo.....
..o......x.x.......x
......x...o...o.x...
.....xo..x.xo...x.x.
o....x.......oo...o.
..o....x......x.....
.o..............x...
o..........x..o.....
.o.....x........x...
...............o.x..
....x..o..x..o......
oo.x...............x
......o...x......o.x
.x...x...x.........o
..o..ooo.x.o.....x.x
x....o.........oo.ox
...ox........o..x...
.........x..........
.......o.....o....x.
.......x.x.o...o....
