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];
		int []a = new int [3];
		int []b = new int [3];
		int []sum = new int [3];
		
		for(int i = 0; i < 3 ;i++) {
			for(int j = 0; j < 3;j++) {
				c[i][j] = sc.nextInt();
			}
		}
		
		boolean jdg = true;
		
		b[0] = c[0][0];
		b[1] = c[0][1];
		b[2] = c[0][2];
		a[0] = 0;
		a[1] = c[1][0] - c[0][0];
		a[2] = c[2][0] - c[0][0];
		
		for(int i = 0; i < 3 ;i++) {
			for(int j = 0; j < 3 ;j++) {
				if(c[i][j] != a[i] + b[j]) {
					jdg =false;
					break;
				}
			}
		}
		
				
		if(jdg) {
			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];
		int []a = new int [3];
		int []b = new int [3];
		int []sum = new int [3];
		
		for(int i = 0; i < 3 ;i++) {
			for(int j = 0; j < 3;j++) {
				c[i][j] = sc.nextInt();
			}
		}
		
		boolean jdg = true;
		
		b[0] = c[0][0];
		b[1] = c[0][1];
		b[2] = c[0][2];
		a[0] = 0;
		a[1] = c[1][0] - c[0][0];
		a[2] = c[2][0] - c[0][0];
		
		for(int i = 0; i < 3 ;i++) {
			for(int j = 0; j < 3 ;j++) {
				if(c[i][j] != a[i] + b[j]) {
					jdg =false;
					break;
				}
			}
		}
		
				
		if(jdg) {
			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];
		int []a = new int [3];
		int []b = new int [3];
		int []sum = new int [3];
		
		for(int i = 0; i < 3 ;i++) {
			for(int j = 0; j < 3;j++) {
				c[i][j] = sc.nextInt();
			}
		}
		
		boolean jdg = true;
		
		b[0] = c[0][0];
		b[1] = c[0][1];
		b[2] = c[0][2];
		a[0] = 0;
		a[1] = c[1][0] - c[0][0];
		a[2] = c[2][0] - c[0][0];
		
		for(int i = 0; i < 3 ;i++) {
			for(int j = 0; j < 3 ;j++) {
				if(c[i][j] != a[i] + b[j]) {
					jdg =false;
					break;
				}
			}
		}
		
				
		if(jdg) {
			System.out.println("Yes");
		}
		else {
			System.out.println("No");
		}

	} main {
		Scanner sc = new Scanner(System.in);
		
		int [][]c = new int [3][3];
		int []a = new int [3];
		int []b = new int [3];
		int []sum = new int [3];
		
		for(int i = 0; i < 3 ;i++) {
			for(int j = 0; j < 3;j++) {
				c[i][j] = sc.nextInt();
			}
		}
		
		boolean jdg = true;
		
		b[0] = c[0][0];
		b[1] = c[0][1];
		b[2] = c[0][2];
		a[0] = 0;
		a[1] = c[1][0] - c[0][0];
		a[2] = c[2][0] - c[0][0];
		
		for(int i = 0; i < 3 ;i++) {
			for(int j = 0; j < 3 ;j++) {
				if(c[i][j] != a[i] + b[j]) {
					jdg =false;
					break;
				}
			}
		}
		
				
		if(jdg) {
			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 int []a = new int [3]; a new int [3] 3 int []b = new int [3]; b new int [3] 3 int []sum = new int [3]; sum new int [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 boolean jdg = true; jdg true b[0] = c[0][0] b[0] b 0 c[0][0] c[0] c 0 0 b[1] = c[0][1] b[1] b 1 c[0][1] c[0] c 0 1 b[2] = c[0][2] b[2] b 2 c[0][2] c[0] c 0 2 a[0] = 0 a[0] a 0 0 a[1] = c[1][0] - c[0][0] a[1] a 1 c[1][0] - c[0][0] c[1][0] c[1] c 1 0 c[0][0] c[0] c 0 0 a[2] = c[2][0] - c[0][0] a[2] a 2 c[2][0] - c[0][0] c[2][0] c[2] c 2 0 c[0][0] c[0] c 0 0 for(int i = 0; i < 3 ;i++) {
			for(int j = 0; j < 3 ;j++) {
				if(c[i][j] != a[i] + b[j]) {
					jdg =false;
					break;
				}
			}
		} 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]) {
					jdg =false;
					break;
				}
			}
		} {
			for(int j = 0; j < 3 ;j++) {
				if(c[i][j] != a[i] + b[j]) {
					jdg =false;
					break;
				}
			}
		} for(int j = 0; j < 3 ;j++) {
				if(c[i][j] != a[i] + b[j]) {
					jdg =false;
					break;
				}
			} int j = 0; int j = 0; j 0 j < 3 j 3 j++ j++ j {
				if(c[i][j] != a[i] + b[j]) {
					jdg =false;
					break;
				}
			} {
				if(c[i][j] != a[i] + b[j]) {
					jdg =false;
					break;
				}
			} if(c[i][j] != a[i] + b[j]) {
					jdg =false;
					break;
				} 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 {
					jdg =false;
					break;
				} jdg =false jdg false break; if(jdg) {
			System.out.println("Yes");
		}
		else {
			System.out.println("No");
		} jdg {
			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];
		int []a = new int [3];
		int []b = new int [3];
		int []sum = new int [3];
		
		for(int i = 0; i < 3 ;i++) {
			for(int j = 0; j < 3;j++) {
				c[i][j] = sc.nextInt();
			}
		}
		
		boolean jdg = true;
		
		b[0] = c[0][0];
		b[1] = c[0][1];
		b[2] = c[0][2];
		a[0] = 0;
		a[1] = c[1][0] - c[0][0];
		a[2] = c[2][0] - c[0][0];
		
		for(int i = 0; i < 3 ;i++) {
			for(int j = 0; j < 3 ;j++) {
				if(c[i][j] != a[i] + b[j]) {
					jdg =false;
					break;
				}
			}
		}
		
				
		if(jdg) {
			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];
		int []a = new int [3];
		int []b = new int [3];
		int []sum = new int [3];
		
		for(int i = 0; i < 3 ;i++) {
			for(int j = 0; j < 3;j++) {
				c[i][j] = sc.nextInt();
			}
		}
		
		boolean jdg = true;
		
		b[0] = c[0][0];
		b[1] = c[0][1];
		b[2] = c[0][2];
		a[0] = 0;
		a[1] = c[1][0] - c[0][0];
		a[2] = c[2][0] - c[0][0];
		
		for(int i = 0; i < 3 ;i++) {
			for(int j = 0; j < 3 ;j++) {
				if(c[i][j] != a[i] + b[j]) {
					jdg =false;
					break;
				}
			}
		}
		
				
		if(jdg) {
			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];
		int []a = new int [3];
		int []b = new int [3];
		int []sum = new int [3];
		
		for(int i = 0; i < 3 ;i++) {
			for(int j = 0; j < 3;j++) {
				c[i][j] = sc.nextInt();
			}
		}
		
		boolean jdg = true;
		
		b[0] = c[0][0];
		b[1] = c[0][1];
		b[2] = c[0][2];
		a[0] = 0;
		a[1] = c[1][0] - c[0][0];
		a[2] = c[2][0] - c[0][0];
		
		for(int i = 0; i < 3 ;i++) {
			for(int j = 0; j < 3 ;j++) {
				if(c[i][j] != a[i] + b[j]) {
					jdg =false;
					break;
				}
			}
		}
		
				
		if(jdg) {
			System.out.println("Yes");
		}
		else {
			System.out.println("No");
		}

	}

}
