board = {{}, {}}

board[1].problem = {
    {5, 3, 0, 0, 7, 0, 0, 0, 0},
    {6, 0, 0, 1, 9, 5, 0, 0, 0},
    {0, 9, 8, 0, 0, 0, 0, 6, 0},
    {8, 0, 0, 0, 6, 0, 0, 0, 3},
    {4, 0, 0, 8, 0, 3, 0, 0, 1},
    {7, 0, 0, 0, 2, 0, 0, 0, 6},
    {0, 6, 0, 0, 0, 0, 2, 8, 0},
    {0, 0, 0, 4, 1, 9, 0, 0, 5},
    {0, 0, 0, 0, 8, 0, 0, 7, 9},
}

board[1].solution = {
    {5, 3, 4, 6, 7, 8, 9, 1, 2},
    {6, 7, 2, 1, 9, 5, 3, 4, 8},
    {1, 9, 8, 3, 4, 2, 5, 6, 7},
    {8, 5, 9, 7, 6, 1, 4, 2, 3},
    {4, 2, 6, 8, 5, 3, 7, 9, 1},
    {7, 1, 3, 9, 2, 4, 8, 5, 6},
    {9, 6, 1, 5, 3, 7, 2, 8, 4},
    {2, 8, 7, 4, 1, 9, 6, 3, 5},
    {3, 4, 5, 2, 8, 6, 1, 7, 9},
}


board[2].problem = {
    {8, 0, 0, 0, 5, 0, 0, 0, 7},
    {0, 6, 1, 0, 0, 0, 0, 0, 0},
    {3, 7, 0, 0, 0, 0, 0, 6, 8},
    {0, 0, 0, 6, 0, 0, 8, 0, 0},
    {0, 1, 0, 0, 9, 0, 0, 2, 0},
    {0, 3, 0, 2, 0, 0, 0, 9, 0},
    {0, 8, 0, 0, 0, 7, 0, 0, 0},
    {0, 0, 0, 0, 0, 0, 4, 0, 1},
    {0, 0, 5, 0, 0, 0, 9, 8, 3},
}