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();
            }
        }
        int sum1 = c[0][0] + c[1][1] + c[2][2];
        int sum2 = c[2][0] + c[0][1] + c[1][2];
        int sum3 = c[1][0] + c[2][1] + c[0][2];
        if(sum1 == sum2 && sum2 == sum3){
            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 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 sum1 = c[0][0] + c[1][1] + c[2][2];
        int sum2 = c[2][0] + c[0][1] + c[1][2];
        int sum3 = c[1][0] + c[2][1] + c[0][2];
        if(sum1 == sum2 && sum2 == sum3){
            System.out.println("Yes");
        }else{
            System.out.println("No");
        }
    }
} 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 sum1 = c[0][0] + c[1][1] + c[2][2];
        int sum2 = c[2][0] + c[0][1] + c[1][2];
        int sum3 = c[1][0] + c[2][1] + c[0][2];
        if(sum1 == sum2 && sum2 == sum3){
            System.out.println("Yes");
        }else{
            System.out.println("No");
        }
    } 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 sum1 = c[0][0] + c[1][1] + c[2][2];
        int sum2 = c[2][0] + c[0][1] + c[1][2];
        int sum3 = c[1][0] + c[2][1] + c[0][2];
        if(sum1 == sum2 && sum2 == sum3){
            System.out.println("Yes");
        }else{
            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 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 sum1 = c[0][0] + c[1][1] + c[2][2]; sum1 c[0][0] + c[1][1] + c[2][2] c[0][0] + c[1][1] + c[2][2] c[0][0] c[0] c 0 0 c[1][1] c[1] c 1 1 c[2][2] c[2] c 2 2 int sum2 = c[2][0] + c[0][1] + c[1][2]; sum2 c[2][0] + c[0][1] + c[1][2] c[2][0] + c[0][1] + c[1][2] c[2][0] c[2] c 2 0 c[0][1] c[0] c 0 1 c[1][2] c[1] c 1 2 int sum3 = c[1][0] + c[2][1] + c[0][2]; sum3 c[1][0] + c[2][1] + c[0][2] c[1][0] + c[2][1] + c[0][2] c[1][0] c[1] c 1 0 c[2][1] c[2] c 2 1 c[0][2] c[0] c 0 2 if(sum1 == sum2 && sum2 == sum3){
            System.out.println("Yes");
        }else{
            System.out.println("No");
        } sum1 == sum2 && sum2 == sum3 sum1 == sum2 sum1 sum2 sum2 == sum3 sum2 sum3 {
            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 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 sum1 = c[0][0] + c[1][1] + c[2][2];
        int sum2 = c[2][0] + c[0][1] + c[1][2];
        int sum3 = c[1][0] + c[2][1] + c[0][2];
        if(sum1 == sum2 && sum2 == sum3){
            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 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 sum1 = c[0][0] + c[1][1] + c[2][2];
        int sum2 = c[2][0] + c[0][1] + c[1][2];
        int sum3 = c[1][0] + c[2][1] + c[0][2];
        if(sum1 == sum2 && sum2 == sum3){
            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 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 sum1 = c[0][0] + c[1][1] + c[2][2];
        int sum2 = c[2][0] + c[0][1] + c[1][2];
        int sum3 = c[1][0] + c[2][1] + c[0][2];
        if(sum1 == sum2 && sum2 == sum3){
            System.out.println("Yes");
        }else{
            System.out.println("No");
        }
    }
}
