package com.company;

import java.util.Arrays;
import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        int n = Integer.parseInt(sc.nextLine());
        int[][] matrix = new int[n][n];

        for (int i = 0; i < n; i++) {
            int[] arr = Arrays.stream(sc.nextLine().split("\\s+"))
                    .mapToInt(Integer::parseInt)
                    .toArray();
            matrix[i] = arr;
        }
        int upperDiagonal = 0;
        int lowerDiagonal = 0;
        for (int i = 0; i < matrix.length; i++) {
            upperDiagonal += matrix[i][i];
        }

        for (int i = 0; i < matrix.length; i++) {
            lowerDiagonal += matrix[i][n - 1 - i];
        }
        System.out.println(Math.abs(upperDiagonal - lowerDiagonal));
    }
}