输入

1
10 10
WB??WB??B?
??WB??W??B
??W?BWB??W
??BW??????
B??BW??BWW
WW??BBWBBB
W?B?????B?
???B?BWB?W
??B?B?B?BW
?BW??WW?W?

输出

NO

唯一的一篇题解在我本机和洛谷IDE死循环了