import java.util.*;
 
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();
            }
        }
        sc.close();

        int a1, b1, b2, b3;
        a1 = 0;
        b1 = c[0][0];
        b2 = c[0][1];
        b3 = c[0][2];
        if(c[1][0] - b1 == c[1][1] - b2 && c[1][1] - b2 == c[1][2] - b3){

        } else {
            System.out.println("No");
            return;
        }
        if(c[2][0] - b1 == c[2][1] - b2 && c[2][1] - b2 == c[2][2] - b3){

        } else {
            System.out.println("No");
            return;
        }
        System.out.println("Yes");
    }
} import java.util.*; util.* 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();
            }
        }
        sc.close();

        int a1, b1, b2, b3;
        a1 = 0;
        b1 = c[0][0];
        b2 = c[0][1];
        b3 = c[0][2];
        if(c[1][0] - b1 == c[1][1] - b2 && c[1][1] - b2 == c[1][2] - b3){

        } else {
            System.out.println("No");
            return;
        }
        if(c[2][0] - b1 == c[2][1] - b2 && c[2][1] - b2 == c[2][2] - b3){

        } else {
            System.out.println("No");
            return;
        }
        System.out.println("Yes");
    }
} 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();
            }
        }
        sc.close();

        int a1, b1, b2, b3;
        a1 = 0;
        b1 = c[0][0];
        b2 = c[0][1];
        b3 = c[0][2];
        if(c[1][0] - b1 == c[1][1] - b2 && c[1][1] - b2 == c[1][2] - b3){

        } else {
            System.out.println("No");
            return;
        }
        if(c[2][0] - b1 == c[2][1] - b2 && c[2][1] - b2 == c[2][2] - b3){

        } else {
            System.out.println("No");
            return;
        }
        System.out.println("Yes");
    } 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();
            }
        }
        sc.close();

        int a1, b1, b2, b3;
        a1 = 0;
        b1 = c[0][0];
        b2 = c[0][1];
        b3 = c[0][2];
        if(c[1][0] - b1 == c[1][1] - b2 && c[1][1] - b2 == c[1][2] - b3){

        } else {
            System.out.println("No");
            return;
        }
        if(c[2][0] - b1 == c[2][1] - b2 && c[2][1] - b2 == c[2][2] - b3){

        } else {
            System.out.println("No");
            return;
        }
        System.out.println("Yes");
    } 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 sc.close() sc.close sc int a1 a1 b1 b1 b2 b2 b3; b3 a1 = 0 a1 0 b1 = c[0][0] b1 c[0][0] c[0] c 0 0 b2 = c[0][1] b2 c[0][1] c[0] c 0 1 b3 = c[0][2] b3 c[0][2] c[0] c 0 2 if(c[1][0] - b1 == c[1][1] - b2 && c[1][1] - b2 == c[1][2] - b3){

        } else {
            System.out.println("No");
            return;
        } c[1][0] - b1 == c[1][1] - b2 && c[1][1] - b2 == c[1][2] - b3 c[1][0] - b1 == c[1][1] - b2 c[1][0] - b1 c[1][0] c[1] c 1 0 b1 c[1][1] - b2 c[1][1] c[1] c 1 1 b2 c[1][1] - b2 == c[1][2] - b3 c[1][1] - b2 c[1][1] c[1] c 1 1 b2 c[1][2] - b3 c[1][2] c[1] c 1 2 b3 {

        } {
            System.out.println("No");
            return;
        } System.out.println("No") System.out.println System.out System System.out "No" return; if(c[2][0] - b1 == c[2][1] - b2 && c[2][1] - b2 == c[2][2] - b3){

        } else {
            System.out.println("No");
            return;
        } c[2][0] - b1 == c[2][1] - b2 && c[2][1] - b2 == c[2][2] - b3 c[2][0] - b1 == c[2][1] - b2 c[2][0] - b1 c[2][0] c[2] c 2 0 b1 c[2][1] - b2 c[2][1] c[2] c 2 1 b2 c[2][1] - b2 == c[2][2] - b3 c[2][1] - b2 c[2][1] c[2] c 2 1 b2 c[2][2] - b3 c[2][2] c[2] c 2 2 b3 {

        } {
            System.out.println("No");
            return;
        } System.out.println("No") System.out.println System.out System System.out "No" return; System.out.println("Yes") System.out.println System.out System System.out "Yes" 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();
            }
        }
        sc.close();

        int a1, b1, b2, b3;
        a1 = 0;
        b1 = c[0][0];
        b2 = c[0][1];
        b3 = c[0][2];
        if(c[1][0] - b1 == c[1][1] - b2 && c[1][1] - b2 == c[1][2] - b3){

        } else {
            System.out.println("No");
            return;
        }
        if(c[2][0] - b1 == c[2][1] - b2 && c[2][1] - b2 == c[2][2] - b3){

        } else {
            System.out.println("No");
            return;
        }
        System.out.println("Yes");
    }
} 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();
            }
        }
        sc.close();

        int a1, b1, b2, b3;
        a1 = 0;
        b1 = c[0][0];
        b2 = c[0][1];
        b3 = c[0][2];
        if(c[1][0] - b1 == c[1][1] - b2 && c[1][1] - b2 == c[1][2] - b3){

        } else {
            System.out.println("No");
            return;
        }
        if(c[2][0] - b1 == c[2][1] - b2 && c[2][1] - b2 == c[2][2] - b3){

        } else {
            System.out.println("No");
            return;
        }
        System.out.println("Yes");
    }
} Main
import java.util.*;
 
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();
            }
        }
        sc.close();

        int a1, b1, b2, b3;
        a1 = 0;
        b1 = c[0][0];
        b2 = c[0][1];
        b3 = c[0][2];
        if(c[1][0] - b1 == c[1][1] - b2 && c[1][1] - b2 == c[1][2] - b3){

        } else {
            System.out.println("No");
            return;
        }
        if(c[2][0] - b1 == c[2][1] - b2 && c[2][1] - b2 == c[2][2] - b3){

        } else {
            System.out.println("No");
            return;
        }
        System.out.println("Yes");
    }
}