text: import sys
  
  import numpy as np
  
  
  def main():
      grid = np.array(sys.stdin.read().split(), dtype=np.int64).reshape(3, 3)
  
      grid = grid - grid[0]
      grid = grid.T
      grid = grid - grid[0]
      if np.all(grid == 0):
          ans = "Yes"
      else:
          ans = "No"
      print(ans)
  
  
  if __name__ == "__main__":
      main()
  