import 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();
			}
		}

		int b[] = {c[0][0] - 0, c[0][1] - 0, c[0][2] - 0};
		int a[] = {0, c[1][0] - b[0], c[2][0] - b[0]};

		for (int i = 0; i < 3; i++) {
			for (int j = 0; j < 3; j++) {
				if (c[i][j] != a[i] + b[j]) {
					System.out.println("No");
					return;
				}
			}
		}
		System.out.println("Yes");
	}
} import java.util.*; util.* java 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();
			}
		}

		int b[] = {c[0][0] - 0, c[0][1] - 0, c[0][2] - 0};
		int a[] = {0, c[1][0] - b[0], c[2][0] - b[0]};

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

		int b[] = {c[0][0] - 0, c[0][1] - 0, c[0][2] - 0};
		int a[] = {0, c[1][0] - b[0], c[2][0] - b[0]};

		for (int i = 0; i < 3; i++) {
			for (int j = 0; j < 3; j++) {
				if (c[i][j] != a[i] + b[j]) {
					System.out.println("No");
					return;
				}
			}
		}
		System.out.println("Yes");
	} 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();
			}
		}

		int b[] = {c[0][0] - 0, c[0][1] - 0, c[0][2] - 0};
		int a[] = {0, c[1][0] - b[0], c[2][0] - b[0]};

		for (int i = 0; i < 3; i++) {
			for (int j = 0; j < 3; j++) {
				if (c[i][j] != a[i] + b[j]) {
					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 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 int b[] = {c[0][0] - 0, c[0][1] - 0, c[0][2] - 0}; b {c[0][0] - 0, c[0][1] - 0, c[0][2] - 0} c[0][0] - 0 c[0][0] c[0] c 0 0 0 c[0][1] - 0 c[0][1] c[0] c 0 1 0 c[0][2] - 0 c[0][2] c[0] c 0 2 0 int a[] = {0, c[1][0] - b[0], c[2][0] - b[0]}; a {0, c[1][0] - b[0], c[2][0] - b[0]} 0 c[1][0] - b[0] c[1][0] c[1] c 1 0 b[0] b 0 c[2][0] - b[0] c[2][0] c[2] c 2 0 b[0] b 0 for (int i = 0; i < 3; i++) {
			for (int j = 0; j < 3; j++) {
				if (c[i][j] != a[i] + b[j]) {
					System.out.println("No");
					return;
				}
			}
		} 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]) {
					System.out.println("No");
					return;
				}
			}
		} {
			for (int j = 0; j < 3; j++) {
				if (c[i][j] != a[i] + b[j]) {
					System.out.println("No");
					return;
				}
			}
		} for (int j = 0; j < 3; j++) {
				if (c[i][j] != a[i] + b[j]) {
					System.out.println("No");
					return;
				}
			} int j = 0; int j = 0; j 0 j < 3 j 3 j++ j++ j {
				if (c[i][j] != a[i] + b[j]) {
					System.out.println("No");
					return;
				}
			} {
				if (c[i][j] != a[i] + b[j]) {
					System.out.println("No");
					return;
				}
			} if (c[i][j] != a[i] + b[j]) {
					System.out.println("No");
					return;
				} 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 {
					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];
		for (int i = 0; i < 3; i++) {
			for (int j = 0; j < 3; j++) {
				c[i][j] = sc.nextInt();
			}
		}

		int b[] = {c[0][0] - 0, c[0][1] - 0, c[0][2] - 0};
		int a[] = {0, c[1][0] - b[0], c[2][0] - b[0]};

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

		int b[] = {c[0][0] - 0, c[0][1] - 0, c[0][2] - 0};
		int a[] = {0, c[1][0] - b[0], c[2][0] - b[0]};

		for (int i = 0; i < 3; i++) {
			for (int j = 0; j < 3; j++) {
				if (c[i][j] != a[i] + b[j]) {
					System.out.println("No");
					return;
				}
			}
		}
		System.out.println("Yes");
	}
} Main
import 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();
			}
		}

		int b[] = {c[0][0] - 0, c[0][1] - 0, c[0][2] - 0};
		int a[] = {0, c[1][0] - b[0], c[2][0] - b[0]};

		for (int i = 0; i < 3; i++) {
			for (int j = 0; j < 3; j++) {
				if (c[i][j] != a[i] + b[j]) {
					System.out.println("No");
					return;
				}
			}
		}
		System.out.println("Yes");
	}
}