public static void main(String[] args) {
        // create initial board from file
        In in = new In(args[0]);
        int N = in.readInt();
        int[][] blocks = new int[N][N];
        for (int i = 0; i < N; i++)
            for (int j = 0; j < N; j++)
                blocks[i][j] = in.readInt();
        Board initial = new Board(blocks);
        System.out.println(initial);
        System.out.println("isGoal test: " + initial.isGoal());
        System.out.println("twin is: \n" + initial.twin());
        for (Board b : initial.neighbors())
            System.out.println(b);
        System.out.println("Hamming method: " + initial.hamming());
        System.out.println("Manhattan method: " + initial.manhattan());
    }