new_contents: #!/usr/bin/env python
  from typing import List
  
  def get_matrix_row_from_input() -> List[int]:
      return [int(index) for index in input().strip().split(' ')]
  
  
  n = int(input().strip())
  primary_diag_sum = 0
  secondary_diag_sum = 0
  for row_count in range(n):
      row = get_matrix_row_from_input()
      primary_diag_sum += row[row_count]
      secondary_diag_sum += row[-1 - row_count]
  
  print(abs(primary_diag_sum - secondary_diag_sum))
  
subject: Add Diagonal Difference HackerRank Problem