20
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..........x.x.......
..........x.....x...
.x..x....x.....xoxx.
....x.o.............
.ox.......o........o
.o..x..x..o...o...o.
...........x..o.o...
............xoo.oox.
.ooo...x.x....x....x
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.x.o............o.o.
...........o...oo...
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x.x.x..............x
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.o.x...........x...x
........o......x....
.........xo.o.......
..o.oo.o........xo.o
