Problem Statement
We have a grid with $H$ horizontal rows and $W$ vertical columns. We denote by square $(i,j)$ the square at the $i$-th row from the top and $j$-th column from the left.
We want to cover this grid with $1 \times 1$ tiles and $1 \times 2$ tiles so that no tiles overlap and everywhere is covered by a tile. (A tile can be rotated.)
Each square has 1, 2, or ? written on it. The character written on square $(i, j)$ is $c_{i,j}$.
A square with 1 written on it must be covered by a $1 \times 1$ tile, and a square with 2 by a $1 \times 2$ tile. A square with ? may be covered by any kind of tile.
Determine if there is such a placement of tiles.
Constraints
$1 \leq H,W \leq 300$$H$and$W$are integers.$c_{i,j}$is one of1,2, and?.
Input
The input is given from Standard Input in the following format:
H W
c_{1,1}c_{1,2}\ldots c_{1,W}
\vdots
c_{H,1}c_{H,2}\ldots c_{H,W}
Output
Print Yes if there is a placement of tiles to satisfy the conditions in the Problem Statement; print No otherwise.
样例
3 4
2221
?1??
2?21
Yes
3 4
2?21
??1?
2?21
No
5 5
11111
11111
11211
11111
11111
No
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