# Ships

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 Sorter: hjfreyer Unknown http://acm.pku.edu.cn/JudgeOnline/problem?id=1138

Ships is problem number 1138 on the Peking University ACM site. We've almost solved it!

```**Description**

Probably everyone who ever attended school knows the game where two opposing
players place a set of ships on a sheet of paper and try to eliminate each
other's ships by guessing their location.

In our version of the game, your opponent has distributed the following seven
ship patterns over a rectangular grid of squares:

xx  xx    xx  x      x   x
xx   xx  xx   xxx  xxx  xxx  xxxx

Each ship pattern covers exactly four squares. The patterns may be rotated but
not mirrored. All patterns are guaranteed to be placed completely within the
boundaries of the rectangle and not to overlap each other, whereas touching
another pattern or the border is allowed.

We assume that we are in the middle of the game and that several squares have
already been uncovered. You will be given a rectangular grid of squares
Every square is marked by one of the following characters:

'x' if a ship covers the square
'o' if no ship covers the square
'.' if the square has not yet been uncovered

Given that information, you are to decide whether you can determine all
remaining 'x' squares with at most one miss, i.e. whether you could uncover
the '.' squares without getting more than one 'o' square before you had all
'x' squares uncovered. This means you are allowed to hit a 'o' if then the
solution becomes unique.

**Input**

The input file contains several game situations. Every test case starts with a
line containing two integers h and w. These define width and height of the game
rectangle, where 2 <= w, h <= 16.

Each of the next h lines contains a string of w characters. Each of these
characters is either `x', `o' or `.', depending on the state of the
corresponding square.

A blank line separates each game from the next. The input file ends with a
game having w = 0 and h = 0. This game should not be processed.

**Output**
For each test case you should first output a line containing the number of the
game, followed by a line containing either `yes.' (if you can determine all `x'
with at most one miss) or `no.' (if you cannot determine all `x' without at
least two misses).

Output a blank line after every game.

**Sample Input**

10 10
.x..x.....
oooooxoooo
oxooxxx...
xxoooooo..
xoooxooo..
ooxxxxoo..
oooooxxoox
ooooooxoox
ooooooooxx
oooooooooo

0 0

**Sample Output**

Game #1
yes.
```