using System;
using System.Linq;
using System.Collections.Generic;

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

        var matrix = new int[rows][];

        for (int row = 0; row < rows; row++)
        {
            matrix[row] = Console.ReadLine().Split(' ').Select(int.Parse).ToArray();
        }
		int sumPrimalDiagonal = 0;
		for (int row = 0; row < rows; row++)
        {
				sumPrimalDiagonal += matrix[row][row];
        }

		int sumSecondaryDiagonal = 0;
		for (int row = 0; row < rows; row++)
        {
				sumSecondaryDiagonal += matrix[row][rows - 1- row];
        }

		int difference = Math.Abs(sumPrimalDiagonal-sumSecondaryDiagonal);
		Console.WriteLine(difference);
	}
}