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