import java.util.*;

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();
            }
        }

        String ans = "Yes";
        boolean bl = true;

        for(int i=0; i<2; i++)
        {
            for(int j=0; j<2; j++)
            {
               if (c[j][i] - c[j][i+1] != c[j+1][i] - c[j+1][i+1]
                || c[i][j] - c[i+1][j] != c[i][j+1] - c[i+1][j+1])
                {
                        ans = "No";
                        break;
                }
            }
        }
        System.out.println(ans);
    }
} import java.util.*; util.* java 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();
            }
        }

        String ans = "Yes";
        boolean bl = true;

        for(int i=0; i<2; i++)
        {
            for(int j=0; j<2; j++)
            {
               if (c[j][i] - c[j][i+1] != c[j+1][i] - c[j+1][i+1]
                || c[i][j] - c[i+1][j] != c[i][j+1] - c[i+1][j+1])
                {
                        ans = "No";
                        break;
                }
            }
        }
        System.out.println(ans);
    }
} 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();
            }
        }

        String ans = "Yes";
        boolean bl = true;

        for(int i=0; i<2; i++)
        {
            for(int j=0; j<2; j++)
            {
               if (c[j][i] - c[j][i+1] != c[j+1][i] - c[j+1][i+1]
                || c[i][j] - c[i+1][j] != c[i][j+1] - c[i+1][j+1])
                {
                        ans = "No";
                        break;
                }
            }
        }
        System.out.println(ans);
    } 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();
            }
        }

        String ans = "Yes";
        boolean bl = true;

        for(int i=0; i<2; i++)
        {
            for(int j=0; j<2; j++)
            {
               if (c[j][i] - c[j][i+1] != c[j+1][i] - c[j+1][i+1]
                || c[i][j] - c[i+1][j] != c[i][j+1] - c[i+1][j+1])
                {
                        ans = "No";
                        break;
                }
            }
        }
        System.out.println(ans);
    } 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 String ans = "Yes"; ans "Yes" boolean bl = true; bl true for(int i=0; i<2; i++)
        {
            for(int j=0; j<2; j++)
            {
               if (c[j][i] - c[j][i+1] != c[j+1][i] - c[j+1][i+1]
                || c[i][j] - c[i+1][j] != c[i][j+1] - c[i+1][j+1])
                {
                        ans = "No";
                        break;
                }
            }
        } int i=0; int i=0; i 0 i<2 i 2 i++ i++ i {
            for(int j=0; j<2; j++)
            {
               if (c[j][i] - c[j][i+1] != c[j+1][i] - c[j+1][i+1]
                || c[i][j] - c[i+1][j] != c[i][j+1] - c[i+1][j+1])
                {
                        ans = "No";
                        break;
                }
            }
        } {
            for(int j=0; j<2; j++)
            {
               if (c[j][i] - c[j][i+1] != c[j+1][i] - c[j+1][i+1]
                || c[i][j] - c[i+1][j] != c[i][j+1] - c[i+1][j+1])
                {
                        ans = "No";
                        break;
                }
            }
        } for(int j=0; j<2; j++)
            {
               if (c[j][i] - c[j][i+1] != c[j+1][i] - c[j+1][i+1]
                || c[i][j] - c[i+1][j] != c[i][j+1] - c[i+1][j+1])
                {
                        ans = "No";
                        break;
                }
            } int j=0; int j=0; j 0 j<2 j 2 j++ j++ j {
               if (c[j][i] - c[j][i+1] != c[j+1][i] - c[j+1][i+1]
                || c[i][j] - c[i+1][j] != c[i][j+1] - c[i+1][j+1])
                {
                        ans = "No";
                        break;
                }
            } {
               if (c[j][i] - c[j][i+1] != c[j+1][i] - c[j+1][i+1]
                || c[i][j] - c[i+1][j] != c[i][j+1] - c[i+1][j+1])
                {
                        ans = "No";
                        break;
                }
            } if (c[j][i] - c[j][i+1] != c[j+1][i] - c[j+1][i+1]
                || c[i][j] - c[i+1][j] != c[i][j+1] - c[i+1][j+1])
                {
                        ans = "No";
                        break;
                } c[j][i] - c[j][i+1] != c[j+1][i] - c[j+1][i+1]
                || c[i][j] - c[i+1][j] != c[i][j+1] - c[i+1][j+1] c[j][i] - c[j][i+1] != c[j+1][i] - c[j+1][i+1] c[j][i] - c[j][i+1] c[j][i] c[j] c j i c[j][i+1] c[j] c j i+1 i 1 c[j+1][i] - c[j+1][i+1] c[j+1][i] c[j+1] c j+1 j 1 i c[j+1][i+1] c[j+1] c j+1 j 1 i+1 i 1 c[i][j] - c[i+1][j] != c[i][j+1] - c[i+1][j+1] c[i][j] - c[i+1][j] c[i][j] c[i] c i j c[i+1][j] c[i+1] c i+1 i 1 j c[i][j+1] - c[i+1][j+1] c[i][j+1] c[i] c i j+1 j 1 c[i+1][j+1] c[i+1] c i+1 i 1 j+1 j 1 {
                        ans = "No";
                        break;
                } ans = "No" ans "No" break; System.out.println(ans) System.out.println System.out System System.out ans String[] args args
import java.util.*;

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();
            }
        }

        String ans = "Yes";
        boolean bl = true;

        for(int i=0; i<2; i++)
        {
            for(int j=0; j<2; j++)
            {
               if (c[j][i] - c[j][i+1] != c[j+1][i] - c[j+1][i+1]
                || c[i][j] - c[i+1][j] != c[i][j+1] - c[i+1][j+1])
                {
                        ans = "No";
                        break;
                }
            }
        }
        System.out.println(ans);
    }
}