import java.util.*;
import java.lang.*;

public class Main{
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        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();
            }
        }
        int kari = c[0][0] - c[0][1];
        if(kari == c[1][0] - c[1][1] && 
           kari == c[2][0] - c[2][1]){
            kari = c[0][1] - c[0][2];
            if(kari == c[1][1] - c[1][2] && 
               kari == c[2][1] - c[2][2]){
                System.out.println("Yes");
            }else{
                System.out.println("No");
            }
        }else{
            System.out.println("No");
        }
        sc.close();
    }
} import java.util.*; util.* java import java.lang.*; lang.* java public class Main{
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        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();
            }
        }
        int kari = c[0][0] - c[0][1];
        if(kari == c[1][0] - c[1][1] && 
           kari == c[2][0] - c[2][1]){
            kari = c[0][1] - c[0][2];
            if(kari == c[1][1] - c[1][2] && 
               kari == c[2][1] - c[2][2]){
                System.out.println("Yes");
            }else{
                System.out.println("No");
            }
        }else{
            System.out.println("No");
        }
        sc.close();
    }
} Main public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        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();
            }
        }
        int kari = c[0][0] - c[0][1];
        if(kari == c[1][0] - c[1][1] && 
           kari == c[2][0] - c[2][1]){
            kari = c[0][1] - c[0][2];
            if(kari == c[1][1] - c[1][2] && 
               kari == c[2][1] - c[2][2]){
                System.out.println("Yes");
            }else{
                System.out.println("No");
            }
        }else{
            System.out.println("No");
        }
        sc.close();
    } main {
        Scanner sc = new Scanner(System.in);
        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();
            }
        }
        int kari = c[0][0] - c[0][1];
        if(kari == c[1][0] - c[1][1] && 
           kari == c[2][0] - c[2][1]){
            kari = c[0][1] - c[0][2];
            if(kari == c[1][1] - c[1][2] && 
               kari == c[2][1] - c[2][2]){
                System.out.println("Yes");
            }else{
                System.out.println("No");
            }
        }else{
            System.out.println("No");
        }
        sc.close();
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) 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 int kari = c[0][0] - c[0][1]; kari c[0][0] - c[0][1] c[0][0] c[0] c 0 0 c[0][1] c[0] c 0 1 if(kari == c[1][0] - c[1][1] && 
           kari == c[2][0] - c[2][1]){
            kari = c[0][1] - c[0][2];
            if(kari == c[1][1] - c[1][2] && 
               kari == c[2][1] - c[2][2]){
                System.out.println("Yes");
            }else{
                System.out.println("No");
            }
        }else{
            System.out.println("No");
        } kari == c[1][0] - c[1][1] && 
           kari == c[2][0] - c[2][1] kari == c[1][0] - c[1][1] kari c[1][0] - c[1][1] c[1][0] c[1] c 1 0 c[1][1] c[1] c 1 1 kari == c[2][0] - c[2][1] kari c[2][0] - c[2][1] c[2][0] c[2] c 2 0 c[2][1] c[2] c 2 1 {
            kari = c[0][1] - c[0][2];
            if(kari == c[1][1] - c[1][2] && 
               kari == c[2][1] - c[2][2]){
                System.out.println("Yes");
            }else{
                System.out.println("No");
            }
        } kari = c[0][1] - c[0][2] kari c[0][1] - c[0][2] c[0][1] c[0] c 0 1 c[0][2] c[0] c 0 2 if(kari == c[1][1] - c[1][2] && 
               kari == c[2][1] - c[2][2]){
                System.out.println("Yes");
            }else{
                System.out.println("No");
            } kari == c[1][1] - c[1][2] && 
               kari == c[2][1] - c[2][2] kari == c[1][1] - c[1][2] kari c[1][1] - c[1][2] c[1][1] c[1] c 1 1 c[1][2] c[1] c 1 2 kari == c[2][1] - c[2][2] kari c[2][1] - c[2][2] c[2][1] c[2] c 2 1 c[2][2] c[2] c 2 2 {
                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" {
            System.out.println("No");
        } System.out.println("No") System.out.println System.out System System.out "No" sc.close() sc.close sc String[] args args public class Main{
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        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();
            }
        }
        int kari = c[0][0] - c[0][1];
        if(kari == c[1][0] - c[1][1] && 
           kari == c[2][0] - c[2][1]){
            kari = c[0][1] - c[0][2];
            if(kari == c[1][1] - c[1][2] && 
               kari == c[2][1] - c[2][2]){
                System.out.println("Yes");
            }else{
                System.out.println("No");
            }
        }else{
            System.out.println("No");
        }
        sc.close();
    }
} public class Main{
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        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();
            }
        }
        int kari = c[0][0] - c[0][1];
        if(kari == c[1][0] - c[1][1] && 
           kari == c[2][0] - c[2][1]){
            kari = c[0][1] - c[0][2];
            if(kari == c[1][1] - c[1][2] && 
               kari == c[2][1] - c[2][2]){
                System.out.println("Yes");
            }else{
                System.out.println("No");
            }
        }else{
            System.out.println("No");
        }
        sc.close();
    }
} Main
import java.util.*;
import java.lang.*;

public class Main{
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        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();
            }
        }
        int kari = c[0][0] - c[0][1];
        if(kari == c[1][0] - c[1][1] && 
           kari == c[2][0] - c[2][1]){
            kari = c[0][1] - c[0][2];
            if(kari == c[1][1] - c[1][2] && 
               kari == c[2][1] - c[2][2]){
                System.out.println("Yes");
            }else{
                System.out.println("No");
            }
        }else{
            System.out.println("No");
        }
        sc.close();
    }
}