import java.util.*;
 
public class Main{
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    int g[][] = new int[3][3];
    int a[] = new int[3];
    int b[] = new int[3];
    
    for(int i=0; i<3; i++){
      for(int j=0; j<3; j++){
        g[i][j] = sc.nextInt();
      }
    }
    if((g[0][0] + g[1][1] == g[0][1] + g[1][0])
       && (g[0][1] + g[1][2] == g[0][2] + g[1][1])
       && (g[1][0] + g[2][1] == g[1][1] + g[2][0])
       && (g[1][1] + g[2][2] == g[1][2] + g[2][1])){
      System.out.println("Yes");
    }else{
      System.out.println("No");
    }
  }
} import java.util.*; util.* java public class Main{
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    int g[][] = new int[3][3];
    int a[] = new int[3];
    int b[] = new int[3];
    
    for(int i=0; i<3; i++){
      for(int j=0; j<3; j++){
        g[i][j] = sc.nextInt();
      }
    }
    if((g[0][0] + g[1][1] == g[0][1] + g[1][0])
       && (g[0][1] + g[1][2] == g[0][2] + g[1][1])
       && (g[1][0] + g[2][1] == g[1][1] + g[2][0])
       && (g[1][1] + g[2][2] == g[1][2] + g[2][1])){
      System.out.println("Yes");
    }else{
      System.out.println("No");
    }
  }
} Main public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    int g[][] = new int[3][3];
    int a[] = new int[3];
    int b[] = new int[3];
    
    for(int i=0; i<3; i++){
      for(int j=0; j<3; j++){
        g[i][j] = sc.nextInt();
      }
    }
    if((g[0][0] + g[1][1] == g[0][1] + g[1][0])
       && (g[0][1] + g[1][2] == g[0][2] + g[1][1])
       && (g[1][0] + g[2][1] == g[1][1] + g[2][0])
       && (g[1][1] + g[2][2] == g[1][2] + g[2][1])){
      System.out.println("Yes");
    }else{
      System.out.println("No");
    }
  } main {
    Scanner sc = new Scanner(System.in);
    int g[][] = new int[3][3];
    int a[] = new int[3];
    int b[] = new int[3];
    
    for(int i=0; i<3; i++){
      for(int j=0; j<3; j++){
        g[i][j] = sc.nextInt();
      }
    }
    if((g[0][0] + g[1][1] == g[0][1] + g[1][0])
       && (g[0][1] + g[1][2] == g[0][2] + g[1][1])
       && (g[1][0] + g[2][1] == g[1][1] + g[2][0])
       && (g[1][1] + g[2][2] == g[1][2] + g[2][1])){
      System.out.println("Yes");
    }else{
      System.out.println("No");
    }
  } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int g[][] = new int[3][3]; g new int[3][3] 3 3 int a[] = new int[3]; a new int[3] 3 int b[] = new int[3]; b new int[3] 3 for(int i=0; i<3; i++){
      for(int j=0; j<3; j++){
        g[i][j] = sc.nextInt();
      }
    } int i=0; int i=0; i 0 i<3 i 3 i++ i++ i {
      for(int j=0; j<3; j++){
        g[i][j] = sc.nextInt();
      }
    } {
      for(int j=0; j<3; j++){
        g[i][j] = sc.nextInt();
      }
    } for(int j=0; j<3; j++){
        g[i][j] = sc.nextInt();
      } int j=0; int j=0; j 0 j<3 j 3 j++ j++ j {
        g[i][j] = sc.nextInt();
      } {
        g[i][j] = sc.nextInt();
      } g[i][j] = sc.nextInt() g[i][j] g[i] g i j sc.nextInt() sc.nextInt sc if((g[0][0] + g[1][1] == g[0][1] + g[1][0])
       && (g[0][1] + g[1][2] == g[0][2] + g[1][1])
       && (g[1][0] + g[2][1] == g[1][1] + g[2][0])
       && (g[1][1] + g[2][2] == g[1][2] + g[2][1])){
      System.out.println("Yes");
    }else{
      System.out.println("No");
    } (g[0][0] + g[1][1] == g[0][1] + g[1][0])
       && (g[0][1] + g[1][2] == g[0][2] + g[1][1])
       && (g[1][0] + g[2][1] == g[1][1] + g[2][0])
       && (g[1][1] + g[2][2] == g[1][2] + g[2][1]) (g[1][0] + g[2][1] == g[1][1] + g[2][0]) (g[0][0] + g[1][1] == g[0][1] + g[1][0])
       && (g[0][1] + g[1][2] == g[0][2] + g[1][1])
       && (g[1][0] + g[2][1] == g[1][1] + g[2][0])
       && (g[1][1] + g[2][2] == g[1][2] + g[2][1]) (g[0][0] + g[1][1] == g[0][1] + g[1][0]) g[0][0] + g[1][1] g[0][0] g[0] g 0 0 g[1][1] g[1] g 1 1 g[0][1] + g[1][0] g[0][1] g[0] g 0 1 g[1][0] g[1] g 1 0 (g[0][1] + g[1][2] == g[0][2] + g[1][1]) g[0][1] + g[1][2] g[0][1] g[0] g 0 1 g[1][2] g[1] g 1 2 g[0][2] + g[1][1] g[0][2] g[0] g 0 2 g[1][1] g[1] g 1 1 (g[1][0] + g[2][1] == g[1][1] + g[2][0]) g[1][0] + g[2][1] g[1][0] g[1] g 1 0 g[2][1] g[2] g 2 1 g[1][1] + g[2][0] g[1][1] g[1] g 1 1 g[2][0] g[2] g 2 0 (g[1][1] + g[2][2] == g[1][2] + g[2][1]) g[1][1] + g[2][2] g[1][1] g[1] g 1 1 g[2][2] g[2] g 2 2 g[1][2] + g[2][1] g[1][2] g[1] g 1 2 g[2][1] g[2] g 2 1 {
      System.out.println("Yes");
    } System.out.println("Yes") System.out.println System.out System System.out "Yes" {
      System.out.println("No");
    } 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 g[][] = new int[3][3];
    int a[] = new int[3];
    int b[] = new int[3];
    
    for(int i=0; i<3; i++){
      for(int j=0; j<3; j++){
        g[i][j] = sc.nextInt();
      }
    }
    if((g[0][0] + g[1][1] == g[0][1] + g[1][0])
       && (g[0][1] + g[1][2] == g[0][2] + g[1][1])
       && (g[1][0] + g[2][1] == g[1][1] + g[2][0])
       && (g[1][1] + g[2][2] == g[1][2] + g[2][1])){
      System.out.println("Yes");
    }else{
      System.out.println("No");
    }
  }
} public class Main{
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    int g[][] = new int[3][3];
    int a[] = new int[3];
    int b[] = new int[3];
    
    for(int i=0; i<3; i++){
      for(int j=0; j<3; j++){
        g[i][j] = sc.nextInt();
      }
    }
    if((g[0][0] + g[1][1] == g[0][1] + g[1][0])
       && (g[0][1] + g[1][2] == g[0][2] + g[1][1])
       && (g[1][0] + g[2][1] == g[1][1] + g[2][0])
       && (g[1][1] + g[2][2] == g[1][2] + g[2][1])){
      System.out.println("Yes");
    }else{
      System.out.println("No");
    }
  }
} Main
import java.util.*;
 
public class Main{
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    int g[][] = new int[3][3];
    int a[] = new int[3];
    int b[] = new int[3];
    
    for(int i=0; i<3; i++){
      for(int j=0; j<3; j++){
        g[i][j] = sc.nextInt();
      }
    }
    if((g[0][0] + g[1][1] == g[0][1] + g[1][0])
       && (g[0][1] + g[1][2] == g[0][2] + g[1][1])
       && (g[1][0] + g[2][1] == g[1][1] + g[2][0])
       && (g[1][1] + g[2][2] == g[1][2] + g[2][1])){
      System.out.println("Yes");
    }else{
      System.out.println("No");
    }
  }
}