using System;
using System.Linq;
namespace Diagonal_Difference
{
    class Program
    {
        static void Main(string[] args)
        {
            int n = int.Parse(Console.ReadLine());
            int[,] matrix = new int[n, n];
            int diagonal = 0;
            for (int row = 0; row < matrix.GetLength(0); row++)
            {
                int[] rows = Console.ReadLine().Split(" ").Select(int.Parse).ToArray();

                for (int col = 0; col < matrix.GetLength(1); col++)
                {
                    matrix[row, col] = rows[col];

                }

            }

            int primaryDiagonal = 0;

            for (int i = 0; i < n; i++)
            {
                primaryDiagonal += matrix[i, i];

            }
            for (int i = 0; i < n; i++)
            {
                diagonal += matrix[n - i - 1, i];
            }

            int difference = diagonal - primaryDiagonal;

            Console.WriteLine(Math.Abs(difference));


        }

    }
}