import java.util.Scanner;

public class Main {

	static int c[][] = new int[3][3];

	@SuppressWarnings("resource")
	public static void main(String args[]) {
		Scanner scanner = new Scanner(System.in);

		for (int i = 0; i < 3; i++) {
			for (int j = 0; j < 3; j++) {
				c[i][j] = scanner.nextInt();
			}
		}

		for (int i = 0; i <= 100; i++) {
			if (judge(i)) {
				System.out.println("Yes");
				return;
			}
		}

		System.out.println("No");

	}

	private static boolean judge(int i) {
		int b1 = c[0][0] - i;
		int b2 = c[0][1] - i;
		int b3 = c[0][2] - i;
		boolean jua2 = false;
		boolean jua3 = false;
		for (int j = 0; j <= 100; j++) {
			if (c[1][0] - b1 == j && c[1][1] - b2 == j && c[1][2] - b3 == j)
				jua2 = true;
		}
		for (int j = 0; j <= 100; j++) {
			if (c[2][0] - b1 == j && c[2][1] - b2 == j && c[2][2] - b3 == j)
				jua3 = true;
		}

		if (0 <= b1 && b1 <= 100 && 0 <= b2 && b2 <= 100 && 0 <= b3 && b3 <= 100 && jua2 && jua3)
			return true;
		else
			return false;

	}

} import java.util.Scanner; Scanner java.util public class Main {

	static int c[][] = new int[3][3];

	@SuppressWarnings("resource")
	public static void main(String args[]) {
		Scanner scanner = new Scanner(System.in);

		for (int i = 0; i < 3; i++) {
			for (int j = 0; j < 3; j++) {
				c[i][j] = scanner.nextInt();
			}
		}

		for (int i = 0; i <= 100; i++) {
			if (judge(i)) {
				System.out.println("Yes");
				return;
			}
		}

		System.out.println("No");

	}

	private static boolean judge(int i) {
		int b1 = c[0][0] - i;
		int b2 = c[0][1] - i;
		int b3 = c[0][2] - i;
		boolean jua2 = false;
		boolean jua3 = false;
		for (int j = 0; j <= 100; j++) {
			if (c[1][0] - b1 == j && c[1][1] - b2 == j && c[1][2] - b3 == j)
				jua2 = true;
		}
		for (int j = 0; j <= 100; j++) {
			if (c[2][0] - b1 == j && c[2][1] - b2 == j && c[2][2] - b3 == j)
				jua3 = true;
		}

		if (0 <= b1 && b1 <= 100 && 0 <= b2 && b2 <= 100 && 0 <= b3 && b3 <= 100 && jua2 && jua3)
			return true;
		else
			return false;

	}

} Main static int c[][] = new int[3][3]; c new int[3][3] 3 3 @SuppressWarnings("resource")
	public static void main(String args[]) {
		Scanner scanner = new Scanner(System.in);

		for (int i = 0; i < 3; i++) {
			for (int j = 0; j < 3; j++) {
				c[i][j] = scanner.nextInt();
			}
		}

		for (int i = 0; i <= 100; i++) {
			if (judge(i)) {
				System.out.println("Yes");
				return;
			}
		}

		System.out.println("No");

	} main {
		Scanner scanner = new Scanner(System.in);

		for (int i = 0; i < 3; i++) {
			for (int j = 0; j < 3; j++) {
				c[i][j] = scanner.nextInt();
			}
		}

		for (int i = 0; i <= 100; i++) {
			if (judge(i)) {
				System.out.println("Yes");
				return;
			}
		}

		System.out.println("No");

	} Scanner scanner = new Scanner(System.in); scanner new Scanner(System.in) 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 <= 100; i++) {
			if (judge(i)) {
				System.out.println("Yes");
				return;
			}
		} int i = 0; int i = 0; i 0 i <= 100 i 100 i++ i++ i {
			if (judge(i)) {
				System.out.println("Yes");
				return;
			}
		} {
			if (judge(i)) {
				System.out.println("Yes");
				return;
			}
		} if (judge(i)) {
				System.out.println("Yes");
				return;
			} judge(i) judge i {
				System.out.println("Yes");
				return;
			} System.out.println("Yes") System.out.println System.out System System.out "Yes" return; System.out.println("No") System.out.println System.out System System.out "No" String args[] args private static boolean judge(int i) {
		int b1 = c[0][0] - i;
		int b2 = c[0][1] - i;
		int b3 = c[0][2] - i;
		boolean jua2 = false;
		boolean jua3 = false;
		for (int j = 0; j <= 100; j++) {
			if (c[1][0] - b1 == j && c[1][1] - b2 == j && c[1][2] - b3 == j)
				jua2 = true;
		}
		for (int j = 0; j <= 100; j++) {
			if (c[2][0] - b1 == j && c[2][1] - b2 == j && c[2][2] - b3 == j)
				jua3 = true;
		}

		if (0 <= b1 && b1 <= 100 && 0 <= b2 && b2 <= 100 && 0 <= b3 && b3 <= 100 && jua2 && jua3)
			return true;
		else
			return false;

	} judge {
		int b1 = c[0][0] - i;
		int b2 = c[0][1] - i;
		int b3 = c[0][2] - i;
		boolean jua2 = false;
		boolean jua3 = false;
		for (int j = 0; j <= 100; j++) {
			if (c[1][0] - b1 == j && c[1][1] - b2 == j && c[1][2] - b3 == j)
				jua2 = true;
		}
		for (int j = 0; j <= 100; j++) {
			if (c[2][0] - b1 == j && c[2][1] - b2 == j && c[2][2] - b3 == j)
				jua3 = true;
		}

		if (0 <= b1 && b1 <= 100 && 0 <= b2 && b2 <= 100 && 0 <= b3 && b3 <= 100 && jua2 && jua3)
			return true;
		else
			return false;

	} int b1 = c[0][0] - i; b1 c[0][0] - i c[0][0] c[0] c 0 0 i int b2 = c[0][1] - i; b2 c[0][1] - i c[0][1] c[0] c 0 1 i int b3 = c[0][2] - i; b3 c[0][2] - i c[0][2] c[0] c 0 2 i boolean jua2 = false; jua2 false boolean jua3 = false; jua3 false for (int j = 0; j <= 100; j++) {
			if (c[1][0] - b1 == j && c[1][1] - b2 == j && c[1][2] - b3 == j)
				jua2 = true;
		} int j = 0; int j = 0; j 0 j <= 100 j 100 j++ j++ j {
			if (c[1][0] - b1 == j && c[1][1] - b2 == j && c[1][2] - b3 == j)
				jua2 = true;
		} {
			if (c[1][0] - b1 == j && c[1][1] - b2 == j && c[1][2] - b3 == j)
				jua2 = true;
		} if (c[1][0] - b1 == j && c[1][1] - b2 == j && c[1][2] - b3 == j)
				jua2 = true; c[1][0] - b1 == j && c[1][1] - b2 == j && c[1][2] - b3 == j c[1][0] - b1 == j && c[1][1] - b2 == j && c[1][2] - b3 == j c[1][0] - b1 == j c[1][0] - b1 c[1][0] c[1] c 1 0 b1 j c[1][1] - b2 == j c[1][1] - b2 c[1][1] c[1] c 1 1 b2 j c[1][2] - b3 == j c[1][2] - b3 c[1][2] c[1] c 1 2 b3 j jua2 = true jua2 true for (int j = 0; j <= 100; j++) {
			if (c[2][0] - b1 == j && c[2][1] - b2 == j && c[2][2] - b3 == j)
				jua3 = true;
		} int j = 0; int j = 0; j 0 j <= 100 j 100 j++ j++ j {
			if (c[2][0] - b1 == j && c[2][1] - b2 == j && c[2][2] - b3 == j)
				jua3 = true;
		} {
			if (c[2][0] - b1 == j && c[2][1] - b2 == j && c[2][2] - b3 == j)
				jua3 = true;
		} if (c[2][0] - b1 == j && c[2][1] - b2 == j && c[2][2] - b3 == j)
				jua3 = true; c[2][0] - b1 == j && c[2][1] - b2 == j && c[2][2] - b3 == j c[2][0] - b1 == j && c[2][1] - b2 == j && c[2][2] - b3 == j c[2][0] - b1 == j c[2][0] - b1 c[2][0] c[2] c 2 0 b1 j c[2][1] - b2 == j c[2][1] - b2 c[2][1] c[2] c 2 1 b2 j c[2][2] - b3 == j c[2][2] - b3 c[2][2] c[2] c 2 2 b3 j jua3 = true jua3 true if (0 <= b1 && b1 <= 100 && 0 <= b2 && b2 <= 100 && 0 <= b3 && b3 <= 100 && jua2 && jua3)
			return true;
		else
			return false; 0 <= b1 && b1 <= 100 && 0 <= b2 && b2 <= 100 && 0 <= b3 && b3 <= 100 && jua2 && jua3 jua2 b3 <= 100 0 <= b3 b2 <= 100 0 <= b2 0 <= b1 && b1 <= 100 && 0 <= b2 && b2 <= 100 && 0 <= b3 && b3 <= 100 && jua2 && jua3 0 <= b1 0 b1 b1 <= 100 b1 100 0 <= b2 0 b2 b2 <= 100 b2 100 0 <= b3 0 b3 b3 <= 100 b3 100 jua2 jua3 return true; true return false; false int i i public class Main {

	static int c[][] = new int[3][3];

	@SuppressWarnings("resource")
	public static void main(String args[]) {
		Scanner scanner = new Scanner(System.in);

		for (int i = 0; i < 3; i++) {
			for (int j = 0; j < 3; j++) {
				c[i][j] = scanner.nextInt();
			}
		}

		for (int i = 0; i <= 100; i++) {
			if (judge(i)) {
				System.out.println("Yes");
				return;
			}
		}

		System.out.println("No");

	}

	private static boolean judge(int i) {
		int b1 = c[0][0] - i;
		int b2 = c[0][1] - i;
		int b3 = c[0][2] - i;
		boolean jua2 = false;
		boolean jua3 = false;
		for (int j = 0; j <= 100; j++) {
			if (c[1][0] - b1 == j && c[1][1] - b2 == j && c[1][2] - b3 == j)
				jua2 = true;
		}
		for (int j = 0; j <= 100; j++) {
			if (c[2][0] - b1 == j && c[2][1] - b2 == j && c[2][2] - b3 == j)
				jua3 = true;
		}

		if (0 <= b1 && b1 <= 100 && 0 <= b2 && b2 <= 100 && 0 <= b3 && b3 <= 100 && jua2 && jua3)
			return true;
		else
			return false;

	}

} public class Main {

	static int c[][] = new int[3][3];

	@SuppressWarnings("resource")
	public static void main(String args[]) {
		Scanner scanner = new Scanner(System.in);

		for (int i = 0; i < 3; i++) {
			for (int j = 0; j < 3; j++) {
				c[i][j] = scanner.nextInt();
			}
		}

		for (int i = 0; i <= 100; i++) {
			if (judge(i)) {
				System.out.println("Yes");
				return;
			}
		}

		System.out.println("No");

	}

	private static boolean judge(int i) {
		int b1 = c[0][0] - i;
		int b2 = c[0][1] - i;
		int b3 = c[0][2] - i;
		boolean jua2 = false;
		boolean jua3 = false;
		for (int j = 0; j <= 100; j++) {
			if (c[1][0] - b1 == j && c[1][1] - b2 == j && c[1][2] - b3 == j)
				jua2 = true;
		}
		for (int j = 0; j <= 100; j++) {
			if (c[2][0] - b1 == j && c[2][1] - b2 == j && c[2][2] - b3 == j)
				jua3 = true;
		}

		if (0 <= b1 && b1 <= 100 && 0 <= b2 && b2 <= 100 && 0 <= b3 && b3 <= 100 && jua2 && jua3)
			return true;
		else
			return false;

	}

} Main
import java.util.Scanner;

public class Main {

	static int c[][] = new int[3][3];

	@SuppressWarnings("resource")
	public static void main(String args[]) {
		Scanner scanner = new Scanner(System.in);

		for (int i = 0; i < 3; i++) {
			for (int j = 0; j < 3; j++) {
				c[i][j] = scanner.nextInt();
			}
		}

		for (int i = 0; i <= 100; i++) {
			if (judge(i)) {
				System.out.println("Yes");
				return;
			}
		}

		System.out.println("No");

	}

	private static boolean judge(int i) {
		int b1 = c[0][0] - i;
		int b2 = c[0][1] - i;
		int b3 = c[0][2] - i;
		boolean jua2 = false;
		boolean jua3 = false;
		for (int j = 0; j <= 100; j++) {
			if (c[1][0] - b1 == j && c[1][1] - b2 == j && c[1][2] - b3 == j)
				jua2 = true;
		}
		for (int j = 0; j <= 100; j++) {
			if (c[2][0] - b1 == j && c[2][1] - b2 == j && c[2][2] - b3 == j)
				jua3 = true;
		}

		if (0 <= b1 && b1 <= 100 && 0 <= b2 && b2 <= 100 && 0 <= b3 && b3 <= 100 && jua2 && jua3)
			return true;
		else
			return false;

	}

}
