Given a 2D board containing 'X' and 'O', capture all regions surrounded by 'X'.

A region is captured by flipping all 'O's into 'X's in that surrounded region.

For example,

X X X X

X O O X

X X O X

X O X X

After running your function, the board should be:

X X X X

X X X X

X X X X

X O X X

The first line contains the number of test cases T. T test cases follow. Each case contains an integer N and M on the first line, followed by N lines, each line contains M characters, each character is ‘X’ or ‘O’.

1 <= T <= 100 

1 <= N * M <= 100000 

Output T boards, one for each test case, the captured 2D board.