using System;
using System.Linq;

namespace Diagonal_Difference
{
    class Program
    {
        static void Main(string[] args)
        {
            int n = int.Parse(Console.ReadLine());

            int[,] arr = new int[n, n];

            for (int i = 0; i < n; i++)
            {
                int[] temp = Console.ReadLine().Split(' ', StringSplitOptions.RemoveEmptyEntries).Select(int.Parse).ToArray();
                for (int j = 0; j < temp.Length; j++)
                {
                    arr[i, j] = temp[j];
                }
            }

            int primarySum = 0;
            int secondarySum = 0;

            for (int row = 0; row < arr.GetLength(0); row++)
            {
                primarySum += arr[row, row];
                secondarySum += arr[row, arr.GetLength(1) - 1 - row];
            }

            Console.WriteLine($"{Math.Abs(primarySum - secondarySum)}");
        }
    }
}