private int getNeedCallsForNextDepth(int[][][] newBoards) {
        int r = 0;
        for (int[][] board : newBoards) {
            if (board == null) {
                continue;
            }
            for (int[] row : board) {
                for (int val : row) {
                    if (val == 0) {
                        r += 2;
                    }
                }
            }
        }
        return r;
    }