public class DiagonalDifference {
    // https://www.hackerrank.com/challenges/diagonal-difference/problem

    public DiagonalDifference() {
        Scanner scanner = new Scanner(System.in);
        int N = scanner.nextInt();
        int[][] arr = new int[N][N];

        for(int i = 0; i < N; i++){
            for(int j = 0; j < N; j++){
                arr[i][j] = scanner.nextInt();
            }
        }

        printAnswer(N, arr);
    }

    public static void printAnswer(int N, int[][] arr) {
        int primaryDiagonal = 0;
        int secondaryDiagonal = 0;
        int j = N;

        for (int i = 0 ; i < N; i++){
            primaryDiagonal += arr[i][i];
            secondaryDiagonal += arr[i][--j];
        }

        System.out.print(Math.abs(primaryDiagonal - secondaryDiagonal));
    }
}