void check(int count)
{
    int x, y = -1;
    for (int i = 0; i < H; i++)
    {
        for (int j = 0; j < W; j++)
        {
            if (board[i][j] == '.')
            {
                x = i;
                y = j;
                break;
            }
        }
        if (y != -1) break;
    }
    if (y == -1)
    {
        if (best < count) best = count;
        return;
    }

    int cnt = 0;
    for (int i = 0; i < H; i++)
        for (int j = 0; j <W; j++) if (board[i][j] != '#') cnt++;
    if ((cnt / cb)+count <= best) return;

    int imsi = blocks.size();

    for (int l = 0; l <imsi; l++)
    {
        int i;
        int tt = blocks[l].size();
        for (i = 0; i < tt; i++) 
            if (board[x + blocks[l][i].first][y + blocks[l][i].second] == '#' || x + blocks[l][i].first<0 || x + blocks[l][i].first>=H || y + blocks[l][i].second<0 || y + blocks[l][i].second>=W) break;
        if (i == tt)
        {
            for (i = 0; i <tt; i++) board[x + blocks[l][i].first][y + blocks[l][i].second] = '#';
            check(count+1);
            for (i = 0; i < tt; i++) board[x + blocks[l][i].first][y + blocks[l][i].second] = '.';
        }
    }
    board[x][y] = '@';
    check(count);
    board[x][y] = '.';
}