public String getAnswer() {
        String input = "08 02 22 97 38 15 00 40 00 75 04 05 07 78 52 12 50 77 91 08\n" +
                "49 49 99 40 17 81 18 57 60 87 17 40 98 43 69 48 04 56 62 00\n" +
                "81 49 31 73 55 79 14 29 93 71 40 67 53 88 30 03 49 13 36 65\n" +
                "52 70 95 23 04 60 11 42 69 24 68 56 01 32 56 71 37 02 36 91\n" +
                "22 31 16 71 51 67 63 89 41 92 36 54 22 40 40 28 66 33 13 80\n" +
                "24 47 32 60 99 03 45 02 44 75 33 53 78 36 84 20 35 17 12 50\n" +
                "32 98 81 28 64 23 67 10 26 38 40 67 59 54 70 66 18 38 64 70\n" +
                "67 26 20 68 02 62 12 20 95 63 94 39 63 08 40 91 66 49 94 21\n" +
                "24 55 58 05 66 73 99 26 97 17 78 78 96 83 14 88 34 89 63 72\n" +
                "21 36 23 09 75 00 76 44 20 45 35 14 00 61 33 97 34 31 33 95\n" +
                "78 17 53 28 22 75 31 67 15 94 03 80 04 62 16 14 09 53 56 92\n" +
                "16 39 05 42 96 35 31 47 55 58 88 24 00 17 54 24 36 29 85 57\n" +
                "86 56 00 48 35 71 89 07 05 44 44 37 44 60 21 58 51 54 17 58\n" +
                "19 80 81 68 05 94 47 69 28 73 92 13 86 52 17 77 04 89 55 40\n" +
                "04 52 08 83 97 35 99 16 07 97 57 32 16 26 26 79 33 27 98 66\n" +
                "88 36 68 87 57 62 20 72 03 46 33 67 46 55 12 32 63 93 53 69\n" +
                "04 42 16 73 38 25 39 11 24 94 72 18 08 46 29 32 40 62 76 36\n" +
                "20 69 36 41 72 30 23 88 34 62 99 69 82 67 59 85 74 04 36 16\n" +
                "20 73 35 29 78 31 90 01 74 31 49 71 48 86 81 16 23 57 05 54\n" +
                "01 70 54 71 83 51 54 69 16 92 33 48 61 43 52 01 89 19 67 48";
        String[] lines = input.split("\n");

        int[][] grid = new int[lines.length][];

        long largestProduct = 1;
        long product;

        int row = 0;
        for (String line : lines) {
            String[] numbers = line.split(" ");
            grid[row] = new int[numbers.length];
            for (int i = 0; i < numbers.length; i++)
                grid[row][i] = Integer.parseInt(numbers[i]);

            row++;
        }

        for (int i = 0;i<16;i++) {
            for (int j = 0;j<16;j++){
                //check vertical
                product = grid[i][j] * grid[i+1][j] * grid[i+2][j] * grid[i+3][j];
                if (product > largestProduct)
                    largestProduct = product;
                //check horizontal
                product = grid[i][j] * grid[i][j+1] * grid[i][j+2] * grid[i][j+3];
                if (product > largestProduct)
                    largestProduct = product;
                //diagonal (\)
                product = grid[i][j] * grid[i+1][j+1] * grid[i+2][j+2] * grid[i+3][j+3];
                if (product > largestProduct)
                    largestProduct = product;
                //diagonal (/)
                product = grid[i+3][j] * grid[i+2][j+1] * grid[i+1][j+2] * grid[i][j+3];
                if (product > largestProduct)
                    largestProduct = product;

            }
        }

        return Long.toString(largestProduct);
    }