import java.util.Scanner;

public class Main { 
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    int[][] c = new int[3][3];
    int max =0;
    for (int i =0; i<3; i++) {
      for (int j =0; j<3; j++) {
        c[i][j] = sc.nextInt();
        max = Math.max(c[i][j],max);
      }
    }
    for (int i =0; i<=max; i++) {
      for (int j =0; j<=max; j++) {
        for (int k =0; k<=max; k++) {
          if (c[1][0] - c[0][0] == j - i && c[1][0] - c[2][0] == j - k) {
            if (c[1][1] - c[0][1] == j - i && c[1][1] - c[2][1] == j - k) {
              if (c[1][2] - c[0][2] == j - i && c[1][2] - c[2][2] == j - k) {
                System.out.println("Yes");
                return;
              }
            }
          }
        }
      }
    }     
    System.out.println("No");  
  }
}     import java.util.Scanner; Scanner java.util public class Main { 
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    int[][] c = new int[3][3];
    int max =0;
    for (int i =0; i<3; i++) {
      for (int j =0; j<3; j++) {
        c[i][j] = sc.nextInt();
        max = Math.max(c[i][j],max);
      }
    }
    for (int i =0; i<=max; i++) {
      for (int j =0; j<=max; j++) {
        for (int k =0; k<=max; k++) {
          if (c[1][0] - c[0][0] == j - i && c[1][0] - c[2][0] == j - k) {
            if (c[1][1] - c[0][1] == j - i && c[1][1] - c[2][1] == j - k) {
              if (c[1][2] - c[0][2] == j - i && c[1][2] - c[2][2] == j - k) {
                System.out.println("Yes");
                return;
              }
            }
          }
        }
      }
    }     
    System.out.println("No");  
  }
} Main public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    int[][] c = new int[3][3];
    int max =0;
    for (int i =0; i<3; i++) {
      for (int j =0; j<3; j++) {
        c[i][j] = sc.nextInt();
        max = Math.max(c[i][j],max);
      }
    }
    for (int i =0; i<=max; i++) {
      for (int j =0; j<=max; j++) {
        for (int k =0; k<=max; k++) {
          if (c[1][0] - c[0][0] == j - i && c[1][0] - c[2][0] == j - k) {
            if (c[1][1] - c[0][1] == j - i && c[1][1] - c[2][1] == j - k) {
              if (c[1][2] - c[0][2] == j - i && c[1][2] - c[2][2] == j - k) {
                System.out.println("Yes");
                return;
              }
            }
          }
        }
      }
    }     
    System.out.println("No");  
  } main {
    Scanner sc = new Scanner(System.in);
    int[][] c = new int[3][3];
    int max =0;
    for (int i =0; i<3; i++) {
      for (int j =0; j<3; j++) {
        c[i][j] = sc.nextInt();
        max = Math.max(c[i][j],max);
      }
    }
    for (int i =0; i<=max; i++) {
      for (int j =0; j<=max; j++) {
        for (int k =0; k<=max; k++) {
          if (c[1][0] - c[0][0] == j - i && c[1][0] - c[2][0] == j - k) {
            if (c[1][1] - c[0][1] == j - i && c[1][1] - c[2][1] == j - k) {
              if (c[1][2] - c[0][2] == j - i && c[1][2] - c[2][2] == j - k) {
                System.out.println("Yes");
                return;
              }
            }
          }
        }
      }
    }     
    System.out.println("No");  
  } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int[][] c = new int[3][3]; c new int[3][3] 3 3 int max =0; max 0 for (int i =0; i<3; i++) {
      for (int j =0; j<3; j++) {
        c[i][j] = sc.nextInt();
        max = Math.max(c[i][j],max);
      }
    } int i =0; int i =0; i 0 i<3 i 3 i++ i++ i {
      for (int j =0; j<3; j++) {
        c[i][j] = sc.nextInt();
        max = Math.max(c[i][j],max);
      }
    } {
      for (int j =0; j<3; j++) {
        c[i][j] = sc.nextInt();
        max = Math.max(c[i][j],max);
      }
    } for (int j =0; j<3; j++) {
        c[i][j] = sc.nextInt();
        max = Math.max(c[i][j],max);
      } int j =0; int j =0; j 0 j<3 j 3 j++ j++ j {
        c[i][j] = sc.nextInt();
        max = Math.max(c[i][j],max);
      } {
        c[i][j] = sc.nextInt();
        max = Math.max(c[i][j],max);
      } c[i][j] = sc.nextInt() c[i][j] c[i] c i j sc.nextInt() sc.nextInt sc max = Math.max(c[i][j],max) max Math.max(c[i][j],max) Math.max Math c[i][j] c[i] c i j max for (int i =0; i<=max; i++) {
      for (int j =0; j<=max; j++) {
        for (int k =0; k<=max; k++) {
          if (c[1][0] - c[0][0] == j - i && c[1][0] - c[2][0] == j - k) {
            if (c[1][1] - c[0][1] == j - i && c[1][1] - c[2][1] == j - k) {
              if (c[1][2] - c[0][2] == j - i && c[1][2] - c[2][2] == j - k) {
                System.out.println("Yes");
                return;
              }
            }
          }
        }
      }
    } int i =0; int i =0; i 0 i<=max i max i++ i++ i {
      for (int j =0; j<=max; j++) {
        for (int k =0; k<=max; k++) {
          if (c[1][0] - c[0][0] == j - i && c[1][0] - c[2][0] == j - k) {
            if (c[1][1] - c[0][1] == j - i && c[1][1] - c[2][1] == j - k) {
              if (c[1][2] - c[0][2] == j - i && c[1][2] - c[2][2] == j - k) {
                System.out.println("Yes");
                return;
              }
            }
          }
        }
      }
    } {
      for (int j =0; j<=max; j++) {
        for (int k =0; k<=max; k++) {
          if (c[1][0] - c[0][0] == j - i && c[1][0] - c[2][0] == j - k) {
            if (c[1][1] - c[0][1] == j - i && c[1][1] - c[2][1] == j - k) {
              if (c[1][2] - c[0][2] == j - i && c[1][2] - c[2][2] == j - k) {
                System.out.println("Yes");
                return;
              }
            }
          }
        }
      }
    } for (int j =0; j<=max; j++) {
        for (int k =0; k<=max; k++) {
          if (c[1][0] - c[0][0] == j - i && c[1][0] - c[2][0] == j - k) {
            if (c[1][1] - c[0][1] == j - i && c[1][1] - c[2][1] == j - k) {
              if (c[1][2] - c[0][2] == j - i && c[1][2] - c[2][2] == j - k) {
                System.out.println("Yes");
                return;
              }
            }
          }
        }
      } int j =0; int j =0; j 0 j<=max j max j++ j++ j {
        for (int k =0; k<=max; k++) {
          if (c[1][0] - c[0][0] == j - i && c[1][0] - c[2][0] == j - k) {
            if (c[1][1] - c[0][1] == j - i && c[1][1] - c[2][1] == j - k) {
              if (c[1][2] - c[0][2] == j - i && c[1][2] - c[2][2] == j - k) {
                System.out.println("Yes");
                return;
              }
            }
          }
        }
      } {
        for (int k =0; k<=max; k++) {
          if (c[1][0] - c[0][0] == j - i && c[1][0] - c[2][0] == j - k) {
            if (c[1][1] - c[0][1] == j - i && c[1][1] - c[2][1] == j - k) {
              if (c[1][2] - c[0][2] == j - i && c[1][2] - c[2][2] == j - k) {
                System.out.println("Yes");
                return;
              }
            }
          }
        }
      } for (int k =0; k<=max; k++) {
          if (c[1][0] - c[0][0] == j - i && c[1][0] - c[2][0] == j - k) {
            if (c[1][1] - c[0][1] == j - i && c[1][1] - c[2][1] == j - k) {
              if (c[1][2] - c[0][2] == j - i && c[1][2] - c[2][2] == j - k) {
                System.out.println("Yes");
                return;
              }
            }
          }
        } int k =0; int k =0; k 0 k<=max k max k++ k++ k {
          if (c[1][0] - c[0][0] == j - i && c[1][0] - c[2][0] == j - k) {
            if (c[1][1] - c[0][1] == j - i && c[1][1] - c[2][1] == j - k) {
              if (c[1][2] - c[0][2] == j - i && c[1][2] - c[2][2] == j - k) {
                System.out.println("Yes");
                return;
              }
            }
          }
        } {
          if (c[1][0] - c[0][0] == j - i && c[1][0] - c[2][0] == j - k) {
            if (c[1][1] - c[0][1] == j - i && c[1][1] - c[2][1] == j - k) {
              if (c[1][2] - c[0][2] == j - i && c[1][2] - c[2][2] == j - k) {
                System.out.println("Yes");
                return;
              }
            }
          }
        } if (c[1][0] - c[0][0] == j - i && c[1][0] - c[2][0] == j - k) {
            if (c[1][1] - c[0][1] == j - i && c[1][1] - c[2][1] == j - k) {
              if (c[1][2] - c[0][2] == j - i && c[1][2] - c[2][2] == j - k) {
                System.out.println("Yes");
                return;
              }
            }
          } c[1][0] - c[0][0] == j - i && c[1][0] - c[2][0] == j - k c[1][0] - c[0][0] == j - i c[1][0] - c[0][0] c[1][0] c[1] c 1 0 c[0][0] c[0] c 0 0 j - i j i c[1][0] - c[2][0] == j - k c[1][0] - c[2][0] c[1][0] c[1] c 1 0 c[2][0] c[2] c 2 0 j - k j k {
            if (c[1][1] - c[0][1] == j - i && c[1][1] - c[2][1] == j - k) {
              if (c[1][2] - c[0][2] == j - i && c[1][2] - c[2][2] == j - k) {
                System.out.println("Yes");
                return;
              }
            }
          } if (c[1][1] - c[0][1] == j - i && c[1][1] - c[2][1] == j - k) {
              if (c[1][2] - c[0][2] == j - i && c[1][2] - c[2][2] == j - k) {
                System.out.println("Yes");
                return;
              }
            } c[1][1] - c[0][1] == j - i && c[1][1] - c[2][1] == j - k c[1][1] - c[0][1] == j - i c[1][1] - c[0][1] c[1][1] c[1] c 1 1 c[0][1] c[0] c 0 1 j - i j i c[1][1] - c[2][1] == j - k c[1][1] - c[2][1] c[1][1] c[1] c 1 1 c[2][1] c[2] c 2 1 j - k j k {
              if (c[1][2] - c[0][2] == j - i && c[1][2] - c[2][2] == j - k) {
                System.out.println("Yes");
                return;
              }
            } if (c[1][2] - c[0][2] == j - i && c[1][2] - c[2][2] == j - k) {
                System.out.println("Yes");
                return;
              } c[1][2] - c[0][2] == j - i && c[1][2] - c[2][2] == j - k c[1][2] - c[0][2] == j - i c[1][2] - c[0][2] c[1][2] c[1] c 1 2 c[0][2] c[0] c 0 2 j - i j i c[1][2] - c[2][2] == j - k c[1][2] - c[2][2] c[1][2] c[1] c 1 2 c[2][2] c[2] c 2 2 j - k j k {
                System.out.println("Yes");
                return;
              } System.out.println("Yes") System.out.println System.out System System.out "Yes" return; System.out.println("No") System.out.println System.out System System.out "No" String[] args args public class Main { 
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    int[][] c = new int[3][3];
    int max =0;
    for (int i =0; i<3; i++) {
      for (int j =0; j<3; j++) {
        c[i][j] = sc.nextInt();
        max = Math.max(c[i][j],max);
      }
    }
    for (int i =0; i<=max; i++) {
      for (int j =0; j<=max; j++) {
        for (int k =0; k<=max; k++) {
          if (c[1][0] - c[0][0] == j - i && c[1][0] - c[2][0] == j - k) {
            if (c[1][1] - c[0][1] == j - i && c[1][1] - c[2][1] == j - k) {
              if (c[1][2] - c[0][2] == j - i && c[1][2] - c[2][2] == j - k) {
                System.out.println("Yes");
                return;
              }
            }
          }
        }
      }
    }     
    System.out.println("No");  
  }
} public class Main { 
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    int[][] c = new int[3][3];
    int max =0;
    for (int i =0; i<3; i++) {
      for (int j =0; j<3; j++) {
        c[i][j] = sc.nextInt();
        max = Math.max(c[i][j],max);
      }
    }
    for (int i =0; i<=max; i++) {
      for (int j =0; j<=max; j++) {
        for (int k =0; k<=max; k++) {
          if (c[1][0] - c[0][0] == j - i && c[1][0] - c[2][0] == j - k) {
            if (c[1][1] - c[0][1] == j - i && c[1][1] - c[2][1] == j - k) {
              if (c[1][2] - c[0][2] == j - i && c[1][2] - c[2][2] == j - k) {
                System.out.println("Yes");
                return;
              }
            }
          }
        }
      }
    }     
    System.out.println("No");  
  }
} Main
import java.util.Scanner;

public class Main { 
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    int[][] c = new int[3][3];
    int max =0;
    for (int i =0; i<3; i++) {
      for (int j =0; j<3; j++) {
        c[i][j] = sc.nextInt();
        max = Math.max(c[i][j],max);
      }
    }
    for (int i =0; i<=max; i++) {
      for (int j =0; j<=max; j++) {
        for (int k =0; k<=max; k++) {
          if (c[1][0] - c[0][0] == j - i && c[1][0] - c[2][0] == j - k) {
            if (c[1][1] - c[0][1] == j - i && c[1][1] - c[2][1] == j - k) {
              if (c[1][2] - c[0][2] == j - i && c[1][2] - c[2][2] == j - k) {
                System.out.println("Yes");
                return;
              }
            }
          }
        }
      }
    }     
    System.out.println("No");  
  }
}    