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

		int[] threesum = new int[6];
		threesum[0] = c[0][0] + c[1][1] + c[2][2];
		threesum[1] = c[0][0] + c[2][1] + c[1][2];
		threesum[2] = c[1][0] + c[0][1] + c[2][2];
		threesum[3] = c[1][0] + c[2][1] + c[0][2];
		threesum[4] = c[2][0] + c[1][1] + c[0][2];
		threesum[5] = c[2][0] + c[0][1] + c[1][2];
		for(int i=1;i<6;i++) {
			if(threesum[0] != threesum[i]) {
				System.out.println("No");
				return;
			}
		}
		System.out.println("Yes");

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

		int[] threesum = new int[6];
		threesum[0] = c[0][0] + c[1][1] + c[2][2];
		threesum[1] = c[0][0] + c[2][1] + c[1][2];
		threesum[2] = c[1][0] + c[0][1] + c[2][2];
		threesum[3] = c[1][0] + c[2][1] + c[0][2];
		threesum[4] = c[2][0] + c[1][1] + c[0][2];
		threesum[5] = c[2][0] + c[0][1] + c[1][2];
		for(int i=1;i<6;i++) {
			if(threesum[0] != threesum[i]) {
				System.out.println("No");
				return;
			}
		}
		System.out.println("Yes");

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

		Scanner sc = new Scanner(System.in);
		int[][] c = new int[3][3];

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

		int[] threesum = new int[6];
		threesum[0] = c[0][0] + c[1][1] + c[2][2];
		threesum[1] = c[0][0] + c[2][1] + c[1][2];
		threesum[2] = c[1][0] + c[0][1] + c[2][2];
		threesum[3] = c[1][0] + c[2][1] + c[0][2];
		threesum[4] = c[2][0] + c[1][1] + c[0][2];
		threesum[5] = c[2][0] + c[0][1] + c[1][2];
		for(int i=1;i<6;i++) {
			if(threesum[0] != threesum[i]) {
				System.out.println("No");
				return;
			}
		}
		System.out.println("Yes");

	} main {

		Scanner sc = new Scanner(System.in);
		int[][] c = new int[3][3];

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

		int[] threesum = new int[6];
		threesum[0] = c[0][0] + c[1][1] + c[2][2];
		threesum[1] = c[0][0] + c[2][1] + c[1][2];
		threesum[2] = c[1][0] + c[0][1] + c[2][2];
		threesum[3] = c[1][0] + c[2][1] + c[0][2];
		threesum[4] = c[2][0] + c[1][1] + c[0][2];
		threesum[5] = c[2][0] + c[0][1] + c[1][2];
		for(int i=1;i<6;i++) {
			if(threesum[0] != threesum[i]) {
				System.out.println("No");
				return;
			}
		}
		System.out.println("Yes");

	} 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 csum = 0; csum 0 for(int i=0;i<3;i++) {
			for(int j=0;j<3;j++) {
				c[i][j] = sc.nextInt();
				csum += c[i][j];
			}
		} 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();
				csum += c[i][j];
			}
		} {
			for(int j=0;j<3;j++) {
				c[i][j] = sc.nextInt();
				csum += c[i][j];
			}
		} for(int j=0;j<3;j++) {
				c[i][j] = sc.nextInt();
				csum += c[i][j];
			} int j=0; int j=0; j 0 j<3 j 3 j++ j++ j {
				c[i][j] = sc.nextInt();
				csum += c[i][j];
			} {
				c[i][j] = sc.nextInt();
				csum += c[i][j];
			} c[i][j] = sc.nextInt() c[i][j] c[i] c i j sc.nextInt() sc.nextInt sc csum += c[i][j] csum c[i][j] c[i] c i j int[] threesum = new int[6]; threesum new int[6] 6 threesum[0] = c[0][0] + c[1][1] + c[2][2] threesum[0] threesum 0 c[0][0] + c[1][1] + c[2][2] c[0][0] + c[1][1] + c[2][2] c[0][0] c[0] c 0 0 c[1][1] c[1] c 1 1 c[2][2] c[2] c 2 2 threesum[1] = c[0][0] + c[2][1] + c[1][2] threesum[1] threesum 1 c[0][0] + c[2][1] + c[1][2] c[0][0] + c[2][1] + c[1][2] c[0][0] c[0] c 0 0 c[2][1] c[2] c 2 1 c[1][2] c[1] c 1 2 threesum[2] = c[1][0] + c[0][1] + c[2][2] threesum[2] threesum 2 c[1][0] + c[0][1] + c[2][2] c[1][0] + c[0][1] + c[2][2] c[1][0] c[1] c 1 0 c[0][1] c[0] c 0 1 c[2][2] c[2] c 2 2 threesum[3] = c[1][0] + c[2][1] + c[0][2] threesum[3] threesum 3 c[1][0] + c[2][1] + c[0][2] c[1][0] + c[2][1] + c[0][2] c[1][0] c[1] c 1 0 c[2][1] c[2] c 2 1 c[0][2] c[0] c 0 2 threesum[4] = c[2][0] + c[1][1] + c[0][2] threesum[4] threesum 4 c[2][0] + c[1][1] + c[0][2] c[2][0] + c[1][1] + c[0][2] c[2][0] c[2] c 2 0 c[1][1] c[1] c 1 1 c[0][2] c[0] c 0 2 threesum[5] = c[2][0] + c[0][1] + c[1][2] threesum[5] threesum 5 c[2][0] + c[0][1] + c[1][2] c[2][0] + c[0][1] + c[1][2] c[2][0] c[2] c 2 0 c[0][1] c[0] c 0 1 c[1][2] c[1] c 1 2 for(int i=1;i<6;i++) {
			if(threesum[0] != threesum[i]) {
				System.out.println("No");
				return;
			}
		} int i=1; int i=1; i 1 i<6 i 6 i++ i++ i {
			if(threesum[0] != threesum[i]) {
				System.out.println("No");
				return;
			}
		} {
			if(threesum[0] != threesum[i]) {
				System.out.println("No");
				return;
			}
		} if(threesum[0] != threesum[i]) {
				System.out.println("No");
				return;
			} threesum[0] != threesum[i] threesum[0] threesum 0 threesum[i] threesum i {
				System.out.println("No");
				return;
			} System.out.println("No") System.out.println System.out System System.out "No" return; System.out.println("Yes") System.out.println System.out System System.out "Yes" 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 csum = 0;
		for(int i=0;i<3;i++) {
			for(int j=0;j<3;j++) {
				c[i][j] = sc.nextInt();
				csum += c[i][j];
			}
		}

		int[] threesum = new int[6];
		threesum[0] = c[0][0] + c[1][1] + c[2][2];
		threesum[1] = c[0][0] + c[2][1] + c[1][2];
		threesum[2] = c[1][0] + c[0][1] + c[2][2];
		threesum[3] = c[1][0] + c[2][1] + c[0][2];
		threesum[4] = c[2][0] + c[1][1] + c[0][2];
		threesum[5] = c[2][0] + c[0][1] + c[1][2];
		for(int i=1;i<6;i++) {
			if(threesum[0] != threesum[i]) {
				System.out.println("No");
				return;
			}
		}
		System.out.println("Yes");

	}
} public class Main {

	public static void main(String args[]) {

		Scanner sc = new Scanner(System.in);
		int[][] c = new int[3][3];

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

		int[] threesum = new int[6];
		threesum[0] = c[0][0] + c[1][1] + c[2][2];
		threesum[1] = c[0][0] + c[2][1] + c[1][2];
		threesum[2] = c[1][0] + c[0][1] + c[2][2];
		threesum[3] = c[1][0] + c[2][1] + c[0][2];
		threesum[4] = c[2][0] + c[1][1] + c[0][2];
		threesum[5] = c[2][0] + c[0][1] + c[1][2];
		for(int i=1;i<6;i++) {
			if(threesum[0] != threesum[i]) {
				System.out.println("No");
				return;
			}
		}
		System.out.println("Yes");

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

		int[] threesum = new int[6];
		threesum[0] = c[0][0] + c[1][1] + c[2][2];
		threesum[1] = c[0][0] + c[2][1] + c[1][2];
		threesum[2] = c[1][0] + c[0][1] + c[2][2];
		threesum[3] = c[1][0] + c[2][1] + c[0][2];
		threesum[4] = c[2][0] + c[1][1] + c[0][2];
		threesum[5] = c[2][0] + c[0][1] + c[1][2];
		for(int i=1;i<6;i++) {
			if(threesum[0] != threesum[i]) {
				System.out.println("No");
				return;
			}
		}
		System.out.println("Yes");

	}
}