import java.io.; import java.math.; import java.security.; import java.text.; import java.util.; import java.util.concurrent.; import java.util.regex.*;

class Result {

/*
 * Complete the 'diagonalDifference' function below.
 *
 * The function is expected to return an INTEGER.
 * The function accepts 2D_INTEGER_ARRAY arr as parameter.
 */

public static int diagonalDifference(List<List<Integer>> arr) {
    int left =0;
    int right =0;
    int n = arr.size();
   for(int i = 0 ; i < n; i++) {
        left += arr.get(i).get(i);
        right += arr.get(i).get(n-1-i);

    }

    return Math.abs(left-right);

}

}

public class Solution { public static void main(String[] args) throws IOException { BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(System.in)); BufferedWriter bufferedWriter = new BufferedWriter(new FileWriter(System.getenv("OUTPUT_PATH")));

    int n = Integer.parseInt(bufferedReader.readLine().trim());

    List<List<Integer>> arr = new ArrayList<>();

    for (int i = 0; i < n; i++) {
        String[] arrRowTempItems = bufferedReader.readLine().replaceAll("\\s+$", "").split(" ");

        List<Integer> arrRowItems = new ArrayList<>();

        for (int j = 0; j < n; j++) {
            int arrItem = Integer.parseInt(arrRowTempItems[j]);
            arrRowItems.add(arrItem);
        }

        arr.add(arrRowItems);
    }

    int result = Result.diagonalDifference(arr);

    bufferedWriter.write(String.valueOf(result));
    bufferedWriter.newLine();

    bufferedReader.close();
    bufferedWriter.close();
}

}