import java.util.Scanner;

public class Main {
	public static void main(String[] args) {

		Scanner scanner=new Scanner(System.in);
		
		int[] a=new int[3];
		int[] b=new int[3];
		int[][] c=new int[3][3];
		
		for(int i=0;i<3;i++) {
			
			for(int j=0;j<3;j++) {
				c[i][j]=scanner.nextInt();
			}
		}
		
		
		for(int i=0;i<3;i++) {
			b[i]=c[0][i];
		}
		
		a[0]=0;
		a[1]=c[1][0]-b[0];
		a[2]=c[2][0]-b[0];
		
		boolean wronganswer=false;
		
		for(int i=0;i<3;i++) {
			
			for(int j=0;j<3;j++) {
				if(c[i][j]!=a[i]+b[j]) {wronganswer=true;};
			}
		}

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

		scanner.close();

	}
} import java.util.Scanner; Scanner java.util public class Main {
	public static void main(String[] args) {

		Scanner scanner=new Scanner(System.in);
		
		int[] a=new int[3];
		int[] b=new int[3];
		int[][] c=new int[3][3];
		
		for(int i=0;i<3;i++) {
			
			for(int j=0;j<3;j++) {
				c[i][j]=scanner.nextInt();
			}
		}
		
		
		for(int i=0;i<3;i++) {
			b[i]=c[0][i];
		}
		
		a[0]=0;
		a[1]=c[1][0]-b[0];
		a[2]=c[2][0]-b[0];
		
		boolean wronganswer=false;
		
		for(int i=0;i<3;i++) {
			
			for(int j=0;j<3;j++) {
				if(c[i][j]!=a[i]+b[j]) {wronganswer=true;};
			}
		}

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

		scanner.close();

	}
} Main public static void main(String[] args) {

		Scanner scanner=new Scanner(System.in);
		
		int[] a=new int[3];
		int[] b=new int[3];
		int[][] c=new int[3][3];
		
		for(int i=0;i<3;i++) {
			
			for(int j=0;j<3;j++) {
				c[i][j]=scanner.nextInt();
			}
		}
		
		
		for(int i=0;i<3;i++) {
			b[i]=c[0][i];
		}
		
		a[0]=0;
		a[1]=c[1][0]-b[0];
		a[2]=c[2][0]-b[0];
		
		boolean wronganswer=false;
		
		for(int i=0;i<3;i++) {
			
			for(int j=0;j<3;j++) {
				if(c[i][j]!=a[i]+b[j]) {wronganswer=true;};
			}
		}

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

		scanner.close();

	} main {

		Scanner scanner=new Scanner(System.in);
		
		int[] a=new int[3];
		int[] b=new int[3];
		int[][] c=new int[3][3];
		
		for(int i=0;i<3;i++) {
			
			for(int j=0;j<3;j++) {
				c[i][j]=scanner.nextInt();
			}
		}
		
		
		for(int i=0;i<3;i++) {
			b[i]=c[0][i];
		}
		
		a[0]=0;
		a[1]=c[1][0]-b[0];
		a[2]=c[2][0]-b[0];
		
		boolean wronganswer=false;
		
		for(int i=0;i<3;i++) {
			
			for(int j=0;j<3;j++) {
				if(c[i][j]!=a[i]+b[j]) {wronganswer=true;};
			}
		}

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

		scanner.close();

	} Scanner scanner=new Scanner(System.in); scanner new Scanner(System.in) int[] a=new int[3]; a new int[3] 3 int[] b=new int[3]; b new int[3] 3 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]=scanner.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]=scanner.nextInt();
			}
		} {
			
			for(int j=0;j<3;j++) {
				c[i][j]=scanner.nextInt();
			}
		} for(int j=0;j<3;j++) {
				c[i][j]=scanner.nextInt();
			} int j=0; int j=0; j 0 j<3 j 3 j++ j++ j {
				c[i][j]=scanner.nextInt();
			} {
				c[i][j]=scanner.nextInt();
			} c[i][j]=scanner.nextInt() c[i][j] c[i] c i j scanner.nextInt() scanner.nextInt scanner for(int i=0;i<3;i++) {
			b[i]=c[0][i];
		} int i=0; int i=0; i 0 i<3 i 3 i++ i++ i {
			b[i]=c[0][i];
		} {
			b[i]=c[0][i];
		} b[i]=c[0][i] b[i] b i c[0][i] c[0] c 0 i a[0]=0 a[0] a 0 0 a[1]=c[1][0]-b[0] a[1] a 1 c[1][0]-b[0] c[1][0] c[1] c 1 0 b[0] b 0 a[2]=c[2][0]-b[0] a[2] a 2 c[2][0]-b[0] c[2][0] c[2] c 2 0 b[0] b 0 boolean wronganswer=false; wronganswer false for(int i=0;i<3;i++) {
			
			for(int j=0;j<3;j++) {
				if(c[i][j]!=a[i]+b[j]) {wronganswer=true;};
			}
		} int i=0; int i=0; i 0 i<3 i 3 i++ i++ i {
			
			for(int j=0;j<3;j++) {
				if(c[i][j]!=a[i]+b[j]) {wronganswer=true;};
			}
		} {
			
			for(int j=0;j<3;j++) {
				if(c[i][j]!=a[i]+b[j]) {wronganswer=true;};
			}
		} for(int j=0;j<3;j++) {
				if(c[i][j]!=a[i]+b[j]) {wronganswer=true;};
			} int j=0; int j=0; j 0 j<3 j 3 j++ j++ j {
				if(c[i][j]!=a[i]+b[j]) {wronganswer=true;};
			} {
				if(c[i][j]!=a[i]+b[j]) {wronganswer=true;};
			} if(c[i][j]!=a[i]+b[j]) {wronganswer=true;} c[i][j]!=a[i]+b[j] c[i][j] c[i] c i j a[i]+b[j] a[i] a i b[j] b j {wronganswer=true;} wronganswer=true wronganswer true if(wronganswer) {
			System.out.println("No");
		}else {
			System.out.println("Yes");
		} wronganswer {
			System.out.println("No");
		} System.out.println("No") System.out.println System.out System System.out "No" {
			System.out.println("Yes");
		} System.out.println("Yes") System.out.println System.out System System.out "Yes" scanner.close() scanner.close scanner String[] args args public class Main {
	public static void main(String[] args) {

		Scanner scanner=new Scanner(System.in);
		
		int[] a=new int[3];
		int[] b=new int[3];
		int[][] c=new int[3][3];
		
		for(int i=0;i<3;i++) {
			
			for(int j=0;j<3;j++) {
				c[i][j]=scanner.nextInt();
			}
		}
		
		
		for(int i=0;i<3;i++) {
			b[i]=c[0][i];
		}
		
		a[0]=0;
		a[1]=c[1][0]-b[0];
		a[2]=c[2][0]-b[0];
		
		boolean wronganswer=false;
		
		for(int i=0;i<3;i++) {
			
			for(int j=0;j<3;j++) {
				if(c[i][j]!=a[i]+b[j]) {wronganswer=true;};
			}
		}

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

		scanner.close();

	}
} public class Main {
	public static void main(String[] args) {

		Scanner scanner=new Scanner(System.in);
		
		int[] a=new int[3];
		int[] b=new int[3];
		int[][] c=new int[3][3];
		
		for(int i=0;i<3;i++) {
			
			for(int j=0;j<3;j++) {
				c[i][j]=scanner.nextInt();
			}
		}
		
		
		for(int i=0;i<3;i++) {
			b[i]=c[0][i];
		}
		
		a[0]=0;
		a[1]=c[1][0]-b[0];
		a[2]=c[2][0]-b[0];
		
		boolean wronganswer=false;
		
		for(int i=0;i<3;i++) {
			
			for(int j=0;j<3;j++) {
				if(c[i][j]!=a[i]+b[j]) {wronganswer=true;};
			}
		}

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

		scanner.close();

	}
} Main
import java.util.Scanner;

public class Main {
	public static void main(String[] args) {

		Scanner scanner=new Scanner(System.in);
		
		int[] a=new int[3];
		int[] b=new int[3];
		int[][] c=new int[3][3];
		
		for(int i=0;i<3;i++) {
			
			for(int j=0;j<3;j++) {
				c[i][j]=scanner.nextInt();
			}
		}
		
		
		for(int i=0;i<3;i++) {
			b[i]=c[0][i];
		}
		
		a[0]=0;
		a[1]=c[1][0]-b[0];
		a[2]=c[2][0]-b[0];
		
		boolean wronganswer=false;
		
		for(int i=0;i<3;i++) {
			
			for(int j=0;j<3;j++) {
				if(c[i][j]!=a[i]+b[j]) {wronganswer=true;};
			}
		}

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

		scanner.close();

	}
}