#!/bin/python3

#

# 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):

# Write your code here

last_index = len(arr) -1

left_to_right_diagonal_sum = 0

right_to_left_diagonal_sum = 0

i, j = 0, 0

while (i <= last_index):

left_to_right_diagonal_sum += arr[i][j]

i+=1

j+=1

p,q = last_index, 0

while (p >= 0):

right_to_left_diagonal_sum += arr[p][q]

p-=1

q+=1

return abs(left_to_right_diagonal_sum - right_to_left_diagonal_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)

print(result)

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

#fptr.close()