def main():
    n = int( input() )

    matrix = [ [int(x) for x in input().strip().split()]  for _ in range(n) ]

    print( absolute_diagonal_difference(matrix) )

def absolute_diagonal_difference(matrix: list) -> int:
    n = len(matrix)
    return abs(
                sum( [ matrix[x][x] for x in range(0, n) ]  )
                    - sum( [ matrix[x][-x - 1] for x in range(0, n) ] )
            )


main()