using System.CodeDom.Compiler;
using System.Collections.Generic;
using System.Collections;
using System.ComponentModel;
using System.Diagnostics.CodeAnalysis;
using System.Globalization;
using System.IO;
using System.Linq;
using System.Reflection;
using System.Runtime.Serialization;
using System.Text.RegularExpressions;
using System.Text;
using System;

class Result
{

    /*
     * Complete the 'diagonalDifference' function below.
     *
     * The function is expected to return an INTEGER.
     * The function accepts 2D_INTEGER_ARRAY arr as parameter.
     */

    public static int diagonalDifference(List<List<int>> arr)
    {
        int sor = 0,
            oszlop = arr.Count,
            al = 0,
            be = 0;

        foreach(List<int> line in arr) sor++;
        for(int i = 0; i <= sor; i++){
            for(int ali = 0; ali < arr.Count; ali++){
                if(i == ali)
                    al += arr[i][ali];
            }
            for(int bei = arr.Count; bei >= 0; bei--){
                if(i + bei == arr.Count)
                    be += arr[i][bei];
            }
        }
        return Math.Abs(al - be);
    }
}

class Solution
{
    public static void Main(string[] args)
    {
        TextWriter textWriter = new StreamWriter(@System.Environment.GetEnvironmentVariable("OUTPUT_PATH"), true);

        int n = Convert.ToInt32(Console.ReadLine().Trim());

        List<List<int>> arr = new List<List<int>>();

        for (int i = 0; i < n; i++)
        {
            arr.Add(Console.ReadLine().TrimEnd().Split(' ').ToList().Select(arrTemp => Convert.ToInt32(arrTemp)).ToList());
        }

        int result = Result.diagonalDifference(arr);

        textWriter.WriteLine(result);

        textWriter.Flush();
        textWriter.Close();
    }
}

/*ERROR
Unhandled Exception:

System.ArgumentOutOfRangeException: Index was out of range. Must be non-negative and less than the size of the collection.

Parameter name: index

  at System.Collections.Generic.List`1[T].get_Item (System.Int32 index) [0x00009] in <04750267503a43e5929c1d1ba19daf3e>:0

  at Result.diagonalDifference (System.Collections.Generic.List`1[T] arr) [0x000b2] in solution.cs:40

  at Solution.Main (System.String[] args) [0x0008e] in solution.cs:62

[ERROR] FATAL UNHANDLED EXCEPTION: System.ArgumentOutOfRangeException: Index was out of range. Must be non-negative and less than the size of the collection.

Parameter name: index

  at System.Collections.Generic.List`1[T].get_Item (System.Int32 index) [0x00009] in <04750267503a43e5929c1d1ba19daf3e>:0

  at Result.diagonalDifference (System.Collections.Generic.List`1[T] arr) [0x000b2] in solution.cs:40

  at Solution.Main (System.String[] args) [0x0008e] in solution.cs:62
*/