using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;


public class Program
{
    public static void Main()
    {
        int n = int.Parse(Console.ReadLine());

        long[,] matrix = new long[n,n];

        long primaryDiagonal = 0;
        long secondaryDiagonal = 0;

        for (int row = 0; row < n; row++)
        {
            int[] rowInts = Console.ReadLine().Split().Select(int.Parse).ToArray();

            for (int col = 0; col < n; col++)
            {
                matrix[row, col] = rowInts[col];

                if (row == col)
                {
                    primaryDiagonal += rowInts[col];
                }

                if (col == ((n - 1) - row))
                {
                    secondaryDiagonal += rowInts[col];
                }
            }
        }

        Console.WriteLine(Math.Abs(primaryDiagonal - secondaryDiagonal));
    }
}