import java.util.Scanner;

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();
		for(int j = 1; j < 3; j++) {
			for(int i = 0; i < 3; i++) c[j][i] -= c[0][i];
		}
		for(int j = 1; j < 3; j++) {
			for(int i = 0; i < 3; i++) c[i][j] -= c[i][0];
		}
		if(c[1][1] == 0 && c[1][2] == 0 && c[2][1] == 0 && c[2][2] == 0) {
			System.out.println("Yes");
		}else {
			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[3][3];
		for(int i = 0; i < 3; i++) for(int j = 0; j < 3; j++) c[i][j] = sc.nextInt();
		for(int j = 1; j < 3; j++) {
			for(int i = 0; i < 3; i++) c[j][i] -= c[0][i];
		}
		for(int j = 1; j < 3; j++) {
			for(int i = 0; i < 3; i++) c[i][j] -= c[i][0];
		}
		if(c[1][1] == 0 && c[1][2] == 0 && c[2][1] == 0 && c[2][2] == 0) {
			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();
		for(int j = 1; j < 3; j++) {
			for(int i = 0; i < 3; i++) c[j][i] -= c[0][i];
		}
		for(int j = 1; j < 3; j++) {
			for(int i = 0; i < 3; i++) c[i][j] -= c[i][0];
		}
		if(c[1][1] == 0 && c[1][2] == 0 && c[2][1] == 0 && c[2][2] == 0) {
			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();
		for(int j = 1; j < 3; j++) {
			for(int i = 0; i < 3; i++) c[j][i] -= c[0][i];
		}
		for(int j = 1; j < 3; j++) {
			for(int i = 0; i < 3; i++) c[i][j] -= c[i][0];
		}
		if(c[1][1] == 0 && c[1][2] == 0 && c[2][1] == 0 && c[2][2] == 0) {
			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(); 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] c[i] c i j sc.nextInt() sc.nextInt sc for(int j = 1; j < 3; j++) {
			for(int i = 0; i < 3; i++) c[j][i] -= c[0][i];
		} int j = 1; int j = 1; j 1 j < 3 j 3 j++ j++ j {
			for(int i = 0; i < 3; i++) c[j][i] -= c[0][i];
		} {
			for(int i = 0; i < 3; i++) c[j][i] -= c[0][i];
		} for(int i = 0; i < 3; i++) c[j][i] -= c[0][i]; int i = 0; int i = 0; i 0 i < 3 i 3 i++ i++ i c[j][i] -= c[0][i]; c[j][i] -= c[0][i] c[j][i] c[j] c j i c[0][i] c[0] c 0 i for(int j = 1; j < 3; j++) {
			for(int i = 0; i < 3; i++) c[i][j] -= c[i][0];
		} int j = 1; int j = 1; j 1 j < 3 j 3 j++ j++ j {
			for(int i = 0; i < 3; i++) c[i][j] -= c[i][0];
		} {
			for(int i = 0; i < 3; i++) c[i][j] -= c[i][0];
		} for(int i = 0; i < 3; i++) c[i][j] -= c[i][0]; int i = 0; int i = 0; i 0 i < 3 i 3 i++ i++ i c[i][j] -= c[i][0]; c[i][j] -= c[i][0] c[i][j] c[i] c i j c[i][0] c[i] c i 0 if(c[1][1] == 0 && c[1][2] == 0 && c[2][1] == 0 && c[2][2] == 0) {
			System.out.println("Yes");
		}else {
			System.out.println("No");
		} c[1][1] == 0 && c[1][2] == 0 && c[2][1] == 0 && c[2][2] == 0 c[2][1] == 0 c[1][1] == 0 && c[1][2] == 0 && c[2][1] == 0 && c[2][2] == 0 c[1][1] == 0 c[1][1] c[1] c 1 1 0 c[1][2] == 0 c[1][2] c[1] c 1 2 0 c[2][1] == 0 c[2][1] c[2] c 2 1 0 c[2][2] == 0 c[2][2] c[2] c 2 2 0 {
			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();
		for(int j = 1; j < 3; j++) {
			for(int i = 0; i < 3; i++) c[j][i] -= c[0][i];
		}
		for(int j = 1; j < 3; j++) {
			for(int i = 0; i < 3; i++) c[i][j] -= c[i][0];
		}
		if(c[1][1] == 0 && c[1][2] == 0 && c[2][1] == 0 && c[2][2] == 0) {
			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();
		for(int j = 1; j < 3; j++) {
			for(int i = 0; i < 3; i++) c[j][i] -= c[0][i];
		}
		for(int j = 1; j < 3; j++) {
			for(int i = 0; i < 3; i++) c[i][j] -= c[i][0];
		}
		if(c[1][1] == 0 && c[1][2] == 0 && c[2][1] == 0 && c[2][2] == 0) {
			System.out.println("Yes");
		}else {
			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[3][3];
		for(int i = 0; i < 3; i++) for(int j = 0; j < 3; j++) c[i][j] = sc.nextInt();
		for(int j = 1; j < 3; j++) {
			for(int i = 0; i < 3; i++) c[j][i] -= c[0][i];
		}
		for(int j = 1; j < 3; j++) {
			for(int i = 0; i < 3; i++) c[i][j] -= c[i][0];
		}
		if(c[1][1] == 0 && c[1][2] == 0 && c[2][1] == 0 && c[2][2] == 0) {
			System.out.println("Yes");
		}else {
			System.out.println("No");
		}
	}
}
