/* package whatever; // don't place package name! */
 
import java.util.*;
import java.lang.*;
import java.io.*;
 
/* Name of the class has to be "Main" only if the class is public. */
class Ideone
{
	public static int find(List<List<Integer>> matrix) {
        int sum1 = 0;
        int sum2 = 0;
        for (int i = 0; i < matrix.size(); i++) {
            sum1 += matrix.get(i).get(i);
            sum2 += matrix.get(i).get(matrix.size() - 1 - i);
        }
        return Math.abs(sum1 - sum2);
    }
	public static void main (String[] args) throws java.lang.Exception
	{
	      Scanner sc = new Scanner(System.in);
 
        int n = sc.nextInt();
        List<List<Integer>> matrix = new ArrayList<>();
        for (int i = 0; i < n; i++) {
            List<Integer> row = new ArrayList<>();
            for (int j = 0; j < n; j++) {
                row.add(sc.nextInt());
            }
            matrix.add(row);
        }
 
        int absoluteDiff = find(matrix);
 
        System.out.println(absoluteDiff);
 
        sc.close();
	}
}

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3
11 2 4
4 5 6
10 8 -12