abs_diff_of_diagonal_sum

import math
import os
import random
import re
import sys


# Complete the 'diagonalDifference' function below.

# The function is expected to return an INTEGER.
# The function accepts 2D_INTEGER_ARRAY arr as parameter.


def diagonalDifference(arr):
    diagonal1_sum = 0
    diagonal2_sum = 0
    
    for i in range(len(arr)):
        diagonal1_sum += arr[i][i]
        diagonal2_sum += arr[i][len(arr)-(i+1)]
        
    absolute_sum = abs(diagonal1_sum - diagonal2_sum)
    
    return absolute_sum

if __name__ == '__main__':
    fptr = open(os.environ['OUTPUT_PATH'], 'w')

    n = int(input().strip())

    arr = []

    for _ in range(n):
        arr.append(list(map(int, input().rstrip().split())))

    result = diagonalDifference(arr)

    fptr.write(str(result) + '\n')

    fptr.close()