output_description: If Takahashi's statement is correct, print `Yes`; otherwise, print `No`.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      c_{1,1} c_{1,2} c_{1,3}
      c_{2,1} c_{2,2} c_{2,3}
      c_{3,1} c_{3,2} c_{3,3}
attempt: ###############################################################################
  
  from sys import stdout
  from bisect import bisect_left as binl
  from copy import copy, deepcopy
  from collections import defaultdict
  
  
  mod = 1
  
  
  def intin():
      input_tuple = input().split()
      if len(input_tuple) <= 1:
          return int(input_tuple[0])
      return tuple(map(int, input_tuple))
  
  
  def intina():
      return [int(i) for i in input().split()]
  
  
  def intinl(count):
      return [intin() for _ in range(count)]
  
  
  def modadd(x, y):
      global mod
      return (x + y) % mod
  
  
  def modmlt(x, y):
      global mod
      return (x * y) % mod
  
  
  def lcm(x, y):
      while y != 0:
          z = x % y
          x = y
          y = z
      return x
  
  
  def combination(x, y):
      assert x >= y
  
      if y > x // 2:
          y = x - y
  
      ret = 1
  
      for i in range(0, y):
          j = x - i
          i = i + 1
  
          ret = ret * j
          ret = ret // i
  
      return ret
  
  
  def get_divisors(x):
      retlist = []
      for i in range(1, int(x**0.5) + 3):
          if x % i == 0:
              retlist.append(i)
              retlist.append(x // i)
      return retlist
  
  
  def get_factors(x):
      retlist = []
      for i in range(2, int(x**0.5) + 3):
          while x % i == 0:
              retlist.append(i)
              x = x // i
      retlist.append(x)
      return retlist
  
  
  def make_linklist(xylist):
      linklist = {}
      for a, b in xylist:
          linklist.setdefault(a, [])
          linklist.setdefault(b, [])
          linklist[a].append(b)
          linklist[b].append(a)
      return linklist
  
  
  def calc_longest_distance(linklist, v=1):
      distance_list = {}
      distance_count = 0
      distance = 0
      vlist_previous = []
      vlist = [v]
      nodecount = len(linklist)
  
      while distance_count < nodecount:
          vlist_next = []
          for v in vlist:
              distance_list[v] = distance
              distance_count += 1
              vlist_next.extend(linklist[v])
          distance += 1
          vlist_to_del = vlist_previous
          vlist_previous = vlist
          vlist = list(set(vlist_next) - set(vlist_to_del))
  
      max_distance = -1
      max_v = None
      for v, distance in distance_list.items():
          if distance > max_distance:
              max_distance = distance
              max_v = v
  
      return (max_distance, max_v)
  
  
  def calc_tree_diameter(linklist, v=1):
      _, u = calc_longest_distance(linklist, v)
      distance, _ = calc_longest_distance(linklist, u)
      return distance
  
  
  class UnionFind:
  
      def __init__(self, n):
          self.parent = [i for i in range(n)]
  
      def root(self, i):
          if self.parent[i] == i:
              return i
          self.parent[i] = self.root(self.parent[i])
          return self.parent[i]
  
      def unite(self, i, j):
          rooti = self.root(i)
          rootj = self.root(j)
          if rooti == rootj:
              return
          if rooti < rootj:
              self.parent[rootj] = rooti
          else:
              self.parent[rooti] = rootj
  
      def same(self, i, j):
          return self.root(i) == self.root(j)
  
  
  ###############################################################################
  
  
  def main():
      c = [intina() for _ in range(3)]
  
      if c[0][0] - c[0][1] != c[1][0] - c[1][1]:
          print("No")
          return
  
      if c[0][0] - c[0][1] != c[2][0] - c[2][1]:
          print("No")
          return
  
      if c[0][0] - c[0][2] != c[1][0] - c[1][2]:
          print("No")
          return
  
      if c[0][0] - c[0][2] != c[2][0] - c[2][2]:
          print("No")
          return
  
      if c[0][0] - c[1][0] != c[0][1] - c[1][1]:
          print("No")
          return
  
      if c[0][0] - c[1][0] != c[0][2] - c[1][2]:
          print("No")
          return
  
      if c[0][0] - c[2][0] != c[0][1] - c[2][1]:
          print("No")
          return
  
      if c[0][0] - c[2][0] != c[0][2] - c[2][2]:
          print("No")
          return
  
      print("Yes")
  
  
  if __name__ == "__main__":
      main()
  
problem_description: Statement
  
  We have a 3 \times 3 grid. A number c_{i, j} is written in the square (i, j),
  where (i, j) denotes the square at the i-th row from the top and the j-th
  column from the left.  
  According to Takahashi, there are six integers a_1, a_2, a_3, b_1, b_2, b_3
  whose values are fixed, and the number written in the square (i, j) is equal
  to a_i + b_j.  
  Determine if he is correct.
samples: [{"input": "1 0 1\n    2 1 2\n    1 0 1", "output": "Yes\n    \n\nTakahashi is correct, since there are possible sets of integers such as:\na_1=0,a_2=1,a_3=0,b_1=1,b_2=0,b_3=1.\n\n* * *"}, {"input": "2 2 2\n    2 1 2\n    2 2 2", "output": "No\n    \n\nTakahashi is incorrect in this case.\n\n* * *"}, {"input": "0 8 8\n    0 8 8\n    0 8 8", "output": "Yes\n    \n\n* * *"}, {"input": "1 8 6\n    2 9 7\n    0 7 7", "output": "No"}]