# Reference: https://www.hackerrank.com/challenges/diagonal-difference
from hackerrank.lists_exercises import find_the_diagonal_difference

n = int(input().strip())
matrix = []
for row_number in range(n):
    captured_row = [int(a_temp) for a_temp in input().strip().split(' ')]
    matrix.append(captured_row)

print(find_the_diagonal_difference(matrix))
 def test_find_the_diagonal_difference(self):
     self.assertEqual(find_the_diagonal_difference([[4, 5], [8, 9]]), 0)
     self.assertEqual(find_the_diagonal_difference([[4, 8], [8, 9]]), 3)
     self.assertEqual(find_the_diagonal_difference([[11, 2, 4], [4, 5, 6], [10, 8, -12]]), 15)