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();
			}
		}
		
		boolean b1 = c[0][0] - c[0][1] == c[1][0] - c[1][1] && c[0][0] - c[0][1] == c[2][0] - c[2][1];
		boolean b2 = c[0][0] - c[0][2] == c[1][0] - c[1][2] && c[0][0] - c[0][2] == c[2][0] - c[2][2];
		boolean b3 = c[0][0] - c[1][0] == c[0][1] - c[1][1] && c[0][0] - c[1][0] == c[0][2] - c[1][2];
		boolean b4 = c[0][0] - c[2][0] == c[0][1] - c[2][1] && c[0][0] - c[2][0] == c[0][2] - c[2][2];
		
		if(b1 && b2 && b3 && b4)
		{
			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();
			}
		}
		
		boolean b1 = c[0][0] - c[0][1] == c[1][0] - c[1][1] && c[0][0] - c[0][1] == c[2][0] - c[2][1];
		boolean b2 = c[0][0] - c[0][2] == c[1][0] - c[1][2] && c[0][0] - c[0][2] == c[2][0] - c[2][2];
		boolean b3 = c[0][0] - c[1][0] == c[0][1] - c[1][1] && c[0][0] - c[1][0] == c[0][2] - c[1][2];
		boolean b4 = c[0][0] - c[2][0] == c[0][1] - c[2][1] && c[0][0] - c[2][0] == c[0][2] - c[2][2];
		
		if(b1 && b2 && b3 && b4)
		{
			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();
			}
		}
		
		boolean b1 = c[0][0] - c[0][1] == c[1][0] - c[1][1] && c[0][0] - c[0][1] == c[2][0] - c[2][1];
		boolean b2 = c[0][0] - c[0][2] == c[1][0] - c[1][2] && c[0][0] - c[0][2] == c[2][0] - c[2][2];
		boolean b3 = c[0][0] - c[1][0] == c[0][1] - c[1][1] && c[0][0] - c[1][0] == c[0][2] - c[1][2];
		boolean b4 = c[0][0] - c[2][0] == c[0][1] - c[2][1] && c[0][0] - c[2][0] == c[0][2] - c[2][2];
		
		if(b1 && b2 && b3 && b4)
		{
			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();
			}
		}
		
		boolean b1 = c[0][0] - c[0][1] == c[1][0] - c[1][1] && c[0][0] - c[0][1] == c[2][0] - c[2][1];
		boolean b2 = c[0][0] - c[0][2] == c[1][0] - c[1][2] && c[0][0] - c[0][2] == c[2][0] - c[2][2];
		boolean b3 = c[0][0] - c[1][0] == c[0][1] - c[1][1] && c[0][0] - c[1][0] == c[0][2] - c[1][2];
		boolean b4 = c[0][0] - c[2][0] == c[0][1] - c[2][1] && c[0][0] - c[2][0] == c[0][2] - c[2][2];
		
		if(b1 && b2 && b3 && b4)
		{
			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();
			}
		} 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 b1 = c[0][0] - c[0][1] == c[1][0] - c[1][1] && c[0][0] - c[0][1] == c[2][0] - c[2][1]; b1 c[0][0] - c[0][1] == c[1][0] - c[1][1] && c[0][0] - c[0][1] == c[2][0] - c[2][1] c[0][0] - c[0][1] == c[1][0] - c[1][1] c[0][0] - c[0][1] c[0][0] c[0] c 0 0 c[0][1] c[0] c 0 1 c[1][0] - c[1][1] c[1][0] c[1] c 1 0 c[1][1] c[1] c 1 1 c[0][0] - c[0][1] == c[2][0] - c[2][1] c[0][0] - c[0][1] c[0][0] c[0] c 0 0 c[0][1] c[0] c 0 1 c[2][0] - c[2][1] c[2][0] c[2] c 2 0 c[2][1] c[2] c 2 1 boolean b2 = c[0][0] - c[0][2] == c[1][0] - c[1][2] && c[0][0] - c[0][2] == c[2][0] - c[2][2]; b2 c[0][0] - c[0][2] == c[1][0] - c[1][2] && c[0][0] - c[0][2] == c[2][0] - c[2][2] c[0][0] - c[0][2] == c[1][0] - c[1][2] c[0][0] - c[0][2] c[0][0] c[0] c 0 0 c[0][2] c[0] c 0 2 c[1][0] - c[1][2] c[1][0] c[1] c 1 0 c[1][2] c[1] c 1 2 c[0][0] - c[0][2] == c[2][0] - c[2][2] c[0][0] - c[0][2] c[0][0] c[0] c 0 0 c[0][2] c[0] c 0 2 c[2][0] - c[2][2] c[2][0] c[2] c 2 0 c[2][2] c[2] c 2 2 boolean b3 = c[0][0] - c[1][0] == c[0][1] - c[1][1] && c[0][0] - c[1][0] == c[0][2] - c[1][2]; b3 c[0][0] - c[1][0] == c[0][1] - c[1][1] && c[0][0] - c[1][0] == c[0][2] - c[1][2] c[0][0] - c[1][0] == c[0][1] - c[1][1] c[0][0] - c[1][0] c[0][0] c[0] c 0 0 c[1][0] c[1] c 1 0 c[0][1] - c[1][1] c[0][1] c[0] c 0 1 c[1][1] c[1] c 1 1 c[0][0] - c[1][0] == c[0][2] - c[1][2] c[0][0] - c[1][0] c[0][0] c[0] c 0 0 c[1][0] c[1] c 1 0 c[0][2] - c[1][2] c[0][2] c[0] c 0 2 c[1][2] c[1] c 1 2 boolean b4 = c[0][0] - c[2][0] == c[0][1] - c[2][1] && c[0][0] - c[2][0] == c[0][2] - c[2][2]; b4 c[0][0] - c[2][0] == c[0][1] - c[2][1] && c[0][0] - c[2][0] == c[0][2] - c[2][2] c[0][0] - c[2][0] == c[0][1] - c[2][1] c[0][0] - c[2][0] c[0][0] c[0] c 0 0 c[2][0] c[2] c 2 0 c[0][1] - c[2][1] c[0][1] c[0] c 0 1 c[2][1] c[2] c 2 1 c[0][0] - c[2][0] == c[0][2] - c[2][2] c[0][0] - c[2][0] c[0][0] c[0] c 0 0 c[2][0] c[2] c 2 0 c[0][2] - c[2][2] c[0][2] c[0] c 0 2 c[2][2] c[2] c 2 2 if(b1 && b2 && b3 && b4)
		{
			System.out.println("Yes");
		}
		else
		{
			System.out.println("No");
		} b1 && b2 && b3 && b4 b3 b1 && b2 && b3 && b4 b1 b2 b3 b4 {
			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();
			}
		}
		
		boolean b1 = c[0][0] - c[0][1] == c[1][0] - c[1][1] && c[0][0] - c[0][1] == c[2][0] - c[2][1];
		boolean b2 = c[0][0] - c[0][2] == c[1][0] - c[1][2] && c[0][0] - c[0][2] == c[2][0] - c[2][2];
		boolean b3 = c[0][0] - c[1][0] == c[0][1] - c[1][1] && c[0][0] - c[1][0] == c[0][2] - c[1][2];
		boolean b4 = c[0][0] - c[2][0] == c[0][1] - c[2][1] && c[0][0] - c[2][0] == c[0][2] - c[2][2];
		
		if(b1 && b2 && b3 && b4)
		{
			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();
			}
		}
		
		boolean b1 = c[0][0] - c[0][1] == c[1][0] - c[1][1] && c[0][0] - c[0][1] == c[2][0] - c[2][1];
		boolean b2 = c[0][0] - c[0][2] == c[1][0] - c[1][2] && c[0][0] - c[0][2] == c[2][0] - c[2][2];
		boolean b3 = c[0][0] - c[1][0] == c[0][1] - c[1][1] && c[0][0] - c[1][0] == c[0][2] - c[1][2];
		boolean b4 = c[0][0] - c[2][0] == c[0][1] - c[2][1] && c[0][0] - c[2][0] == c[0][2] - c[2][2];
		
		if(b1 && b2 && b3 && b4)
		{
			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();
			}
		}
		
		boolean b1 = c[0][0] - c[0][1] == c[1][0] - c[1][1] && c[0][0] - c[0][1] == c[2][0] - c[2][1];
		boolean b2 = c[0][0] - c[0][2] == c[1][0] - c[1][2] && c[0][0] - c[0][2] == c[2][0] - c[2][2];
		boolean b3 = c[0][0] - c[1][0] == c[0][1] - c[1][1] && c[0][0] - c[1][0] == c[0][2] - c[1][2];
		boolean b4 = c[0][0] - c[2][0] == c[0][1] - c[2][1] && c[0][0] - c[2][0] == c[0][2] - c[2][2];
		
		if(b1 && b2 && b3 && b4)
		{
			System.out.println("Yes");
		}
		else
		{
			System.out.println("No");
		}
		
	}
}