class Solution(object):
    def gameOfLife(self, board):
        """
        :type board: List[List[int]]
        :rtype: void Do not return anything, modify board in-place instead.
        """
        
        m=len(board)
        n=len(board[0])
        if m==0 or n==0:
            return 
        
        for i in xrange(m):
            for j in xrange(n):
                
                count=0
                for a in xrange(max(0,i-1),min(m,i+2)):
                    for b in xrange(max(0,j-1),min(n,j+2)):
                        if board[a][b]&1:
                            count+=1
                if (count==4 and (board[i][j]&1)) or count==3:
                    board[i][j]|=2
        for i in xrange(m):
            for j in xrange(n):
                board[i][j]>>=1