import java.util.Scanner;
public class Main{
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    int[] c=new int[9];
    for(int i=0;i<9;i++)c[i]=sc.nextInt();
    for(int i=0;i<=Math.max(c[0], Math.max(c[1], c[2]));i++) {
    	int a1=i,b1=c[0]-a1,b2=c[1]-a1,b3=c[2]-a1,a2=c[3]-b1,a3=c[6]-b1;
    	if(a1+b1==c[0] && a1+b2==c[1]&& a1+b3==c[2]&& a2+b1==c[3]&& a2+b2==c[4]&& a2+b3==c[5]&& a3+b1==c[6]&& a3+b2==c[7]&& a3+b3==c[8]) {
    		System.out.println("Yes");
    		//System.out.println(a1+" "+a2+" "+a3+" "+b1+" "+b2+" "+b3);
    		System.exit(0);
    	}
    }
    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[] c=new int[9];
    for(int i=0;i<9;i++)c[i]=sc.nextInt();
    for(int i=0;i<=Math.max(c[0], Math.max(c[1], c[2]));i++) {
    	int a1=i,b1=c[0]-a1,b2=c[1]-a1,b3=c[2]-a1,a2=c[3]-b1,a3=c[6]-b1;
    	if(a1+b1==c[0] && a1+b2==c[1]&& a1+b3==c[2]&& a2+b1==c[3]&& a2+b2==c[4]&& a2+b3==c[5]&& a3+b1==c[6]&& a3+b2==c[7]&& a3+b3==c[8]) {
    		System.out.println("Yes");
    		//System.out.println(a1+" "+a2+" "+a3+" "+b1+" "+b2+" "+b3);
    		System.exit(0);
    	}
    }
    System.out.println("No");
  }
} Main public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    int[] c=new int[9];
    for(int i=0;i<9;i++)c[i]=sc.nextInt();
    for(int i=0;i<=Math.max(c[0], Math.max(c[1], c[2]));i++) {
    	int a1=i,b1=c[0]-a1,b2=c[1]-a1,b3=c[2]-a1,a2=c[3]-b1,a3=c[6]-b1;
    	if(a1+b1==c[0] && a1+b2==c[1]&& a1+b3==c[2]&& a2+b1==c[3]&& a2+b2==c[4]&& a2+b3==c[5]&& a3+b1==c[6]&& a3+b2==c[7]&& a3+b3==c[8]) {
    		System.out.println("Yes");
    		//System.out.println(a1+" "+a2+" "+a3+" "+b1+" "+b2+" "+b3);
    		System.exit(0);
    	}
    }
    System.out.println("No");
  } main {
    Scanner sc = new Scanner(System.in);
    int[] c=new int[9];
    for(int i=0;i<9;i++)c[i]=sc.nextInt();
    for(int i=0;i<=Math.max(c[0], Math.max(c[1], c[2]));i++) {
    	int a1=i,b1=c[0]-a1,b2=c[1]-a1,b3=c[2]-a1,a2=c[3]-b1,a3=c[6]-b1;
    	if(a1+b1==c[0] && a1+b2==c[1]&& a1+b3==c[2]&& a2+b1==c[3]&& a2+b2==c[4]&& a2+b3==c[5]&& a3+b1==c[6]&& a3+b2==c[7]&& a3+b3==c[8]) {
    		System.out.println("Yes");
    		//System.out.println(a1+" "+a2+" "+a3+" "+b1+" "+b2+" "+b3);
    		System.exit(0);
    	}
    }
    System.out.println("No");
  } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int[] c=new int[9]; c new int[9] 9 for(int i=0;i<9;i++)c[i]=sc.nextInt(); int i=0; int i=0; i 0 i<9 i 9 i++ i++ i c[i]=sc.nextInt(); c[i]=sc.nextInt() c[i] c i sc.nextInt() sc.nextInt sc for(int i=0;i<=Math.max(c[0], Math.max(c[1], c[2]));i++) {
    	int a1=i,b1=c[0]-a1,b2=c[1]-a1,b3=c[2]-a1,a2=c[3]-b1,a3=c[6]-b1;
    	if(a1+b1==c[0] && a1+b2==c[1]&& a1+b3==c[2]&& a2+b1==c[3]&& a2+b2==c[4]&& a2+b3==c[5]&& a3+b1==c[6]&& a3+b2==c[7]&& a3+b3==c[8]) {
    		System.out.println("Yes");
    		//System.out.println(a1+" "+a2+" "+a3+" "+b1+" "+b2+" "+b3);
    		System.exit(0);
    	}
    } int i=0; int i=0; i 0 i<=Math.max(c[0], Math.max(c[1], c[2])) i Math.max(c[0], Math.max(c[1], c[2])) Math.max Math c[0] c 0 Math.max(c[1], c[2]) Math.max Math c[1] c 1 c[2] c 2 i++ i++ i {
    	int a1=i,b1=c[0]-a1,b2=c[1]-a1,b3=c[2]-a1,a2=c[3]-b1,a3=c[6]-b1;
    	if(a1+b1==c[0] && a1+b2==c[1]&& a1+b3==c[2]&& a2+b1==c[3]&& a2+b2==c[4]&& a2+b3==c[5]&& a3+b1==c[6]&& a3+b2==c[7]&& a3+b3==c[8]) {
    		System.out.println("Yes");
    		//System.out.println(a1+" "+a2+" "+a3+" "+b1+" "+b2+" "+b3);
    		System.exit(0);
    	}
    } {
    	int a1=i,b1=c[0]-a1,b2=c[1]-a1,b3=c[2]-a1,a2=c[3]-b1,a3=c[6]-b1;
    	if(a1+b1==c[0] && a1+b2==c[1]&& a1+b3==c[2]&& a2+b1==c[3]&& a2+b2==c[4]&& a2+b3==c[5]&& a3+b1==c[6]&& a3+b2==c[7]&& a3+b3==c[8]) {
    		System.out.println("Yes");
    		//System.out.println(a1+" "+a2+" "+a3+" "+b1+" "+b2+" "+b3);
    		System.exit(0);
    	}
    } int a1=i a1 i b1=c[0]-a1 b1 c[0]-a1 c[0] c 0 a1 b2=c[1]-a1 b2 c[1]-a1 c[1] c 1 a1 b3=c[2]-a1 b3 c[2]-a1 c[2] c 2 a1 a2=c[3]-b1 a2 c[3]-b1 c[3] c 3 b1 a3=c[6]-b1; a3 c[6]-b1 c[6] c 6 b1 if(a1+b1==c[0] && a1+b2==c[1]&& a1+b3==c[2]&& a2+b1==c[3]&& a2+b2==c[4]&& a2+b3==c[5]&& a3+b1==c[6]&& a3+b2==c[7]&& a3+b3==c[8]) {
    		System.out.println("Yes");
    		//System.out.println(a1+" "+a2+" "+a3+" "+b1+" "+b2+" "+b3);
    		System.exit(0);
    	} a1+b1==c[0] && a1+b2==c[1]&& a1+b3==c[2]&& a2+b1==c[3]&& a2+b2==c[4]&& a2+b3==c[5]&& a3+b1==c[6]&& a3+b2==c[7]&& a3+b3==c[8] a3+b2==c[7] a3+b1==c[6] a2+b3==c[5] a2+b2==c[4] a2+b1==c[3] a1+b3==c[2] a1+b1==c[0] && a1+b2==c[1]&& a1+b3==c[2]&& a2+b1==c[3]&& a2+b2==c[4]&& a2+b3==c[5]&& a3+b1==c[6]&& a3+b2==c[7]&& a3+b3==c[8] a1+b1==c[0] a1+b1 a1 b1 c[0] c 0 a1+b2==c[1] a1+b2 a1 b2 c[1] c 1 a1+b3==c[2] a1+b3 a1 b3 c[2] c 2 a2+b1==c[3] a2+b1 a2 b1 c[3] c 3 a2+b2==c[4] a2+b2 a2 b2 c[4] c 4 a2+b3==c[5] a2+b3 a2 b3 c[5] c 5 a3+b1==c[6] a3+b1 a3 b1 c[6] c 6 a3+b2==c[7] a3+b2 a3 b2 c[7] c 7 a3+b3==c[8] a3+b3 a3 b3 c[8] c 8 {
    		System.out.println("Yes");
    		//System.out.println(a1+" "+a2+" "+a3+" "+b1+" "+b2+" "+b3);
    		System.exit(0);
    	} System.out.println("Yes") System.out.println System.out System System.out "Yes" System.exit(0) System.exit System 0 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[9];
    for(int i=0;i<9;i++)c[i]=sc.nextInt();
    for(int i=0;i<=Math.max(c[0], Math.max(c[1], c[2]));i++) {
    	int a1=i,b1=c[0]-a1,b2=c[1]-a1,b3=c[2]-a1,a2=c[3]-b1,a3=c[6]-b1;
    	if(a1+b1==c[0] && a1+b2==c[1]&& a1+b3==c[2]&& a2+b1==c[3]&& a2+b2==c[4]&& a2+b3==c[5]&& a3+b1==c[6]&& a3+b2==c[7]&& a3+b3==c[8]) {
    		System.out.println("Yes");
    		//System.out.println(a1+" "+a2+" "+a3+" "+b1+" "+b2+" "+b3);
    		System.exit(0);
    	}
    }
    System.out.println("No");
  }
} public class Main{
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    int[] c=new int[9];
    for(int i=0;i<9;i++)c[i]=sc.nextInt();
    for(int i=0;i<=Math.max(c[0], Math.max(c[1], c[2]));i++) {
    	int a1=i,b1=c[0]-a1,b2=c[1]-a1,b3=c[2]-a1,a2=c[3]-b1,a3=c[6]-b1;
    	if(a1+b1==c[0] && a1+b2==c[1]&& a1+b3==c[2]&& a2+b1==c[3]&& a2+b2==c[4]&& a2+b3==c[5]&& a3+b1==c[6]&& a3+b2==c[7]&& a3+b3==c[8]) {
    		System.out.println("Yes");
    		//System.out.println(a1+" "+a2+" "+a3+" "+b1+" "+b2+" "+b3);
    		System.exit(0);
    	}
    }
    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[] c=new int[9];
    for(int i=0;i<9;i++)c[i]=sc.nextInt();
    for(int i=0;i<=Math.max(c[0], Math.max(c[1], c[2]));i++) {
    	int a1=i,b1=c[0]-a1,b2=c[1]-a1,b3=c[2]-a1,a2=c[3]-b1,a3=c[6]-b1;
    	if(a1+b1==c[0] && a1+b2==c[1]&& a1+b3==c[2]&& a2+b1==c[3]&& a2+b2==c[4]&& a2+b3==c[5]&& a3+b1==c[6]&& a3+b2==c[7]&& a3+b3==c[8]) {
    		System.out.println("Yes");
    		//System.out.println(a1+" "+a2+" "+a3+" "+b1+" "+b2+" "+b3);
    		System.exit(0);
    	}
    }
    System.out.println("No");
  }
}