import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int[] a = new int[4];
		int[] b = new int[4];
		int[][] c = new int[4][4];
		for(int i=1;i<=3;i++) {
			for(int j=1; j<=3; j++) {
				c[i][j] = sc.nextInt();
			}
		}
		a[1] = c[1][1];
		a[2] = c[2][1];
		a[3] = c[3][1];
		b[1] = 0;
		b[2] = c[1][2] - c[1][1];
		b[3] = c[1][3] - c[1][1];

		boolean ans = true;
		int numbers[] = {2,3};//[1]
		 for (int i : numbers) {
			 for(int j: numbers) {
				 if(a[i] + b[j] == c[i][j]);
				 else ans = false;
			 }
        }

		if(ans) 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[] a = new int[4];
		int[] b = new int[4];
		int[][] c = new int[4][4];
		for(int i=1;i<=3;i++) {
			for(int j=1; j<=3; j++) {
				c[i][j] = sc.nextInt();
			}
		}
		a[1] = c[1][1];
		a[2] = c[2][1];
		a[3] = c[3][1];
		b[1] = 0;
		b[2] = c[1][2] - c[1][1];
		b[3] = c[1][3] - c[1][1];

		boolean ans = true;
		int numbers[] = {2,3};//[1]
		 for (int i : numbers) {
			 for(int j: numbers) {
				 if(a[i] + b[j] == c[i][j]);
				 else ans = false;
			 }
        }

		if(ans) System.out.println("Yes");
		else System.out.println("No");

	}
} Main public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int[] a = new int[4];
		int[] b = new int[4];
		int[][] c = new int[4][4];
		for(int i=1;i<=3;i++) {
			for(int j=1; j<=3; j++) {
				c[i][j] = sc.nextInt();
			}
		}
		a[1] = c[1][1];
		a[2] = c[2][1];
		a[3] = c[3][1];
		b[1] = 0;
		b[2] = c[1][2] - c[1][1];
		b[3] = c[1][3] - c[1][1];

		boolean ans = true;
		int numbers[] = {2,3};//[1]
		 for (int i : numbers) {
			 for(int j: numbers) {
				 if(a[i] + b[j] == c[i][j]);
				 else ans = false;
			 }
        }

		if(ans) System.out.println("Yes");
		else System.out.println("No");

	} main {
		Scanner sc = new Scanner(System.in);
		int[] a = new int[4];
		int[] b = new int[4];
		int[][] c = new int[4][4];
		for(int i=1;i<=3;i++) {
			for(int j=1; j<=3; j++) {
				c[i][j] = sc.nextInt();
			}
		}
		a[1] = c[1][1];
		a[2] = c[2][1];
		a[3] = c[3][1];
		b[1] = 0;
		b[2] = c[1][2] - c[1][1];
		b[3] = c[1][3] - c[1][1];

		boolean ans = true;
		int numbers[] = {2,3};//[1]
		 for (int i : numbers) {
			 for(int j: numbers) {
				 if(a[i] + b[j] == c[i][j]);
				 else ans = false;
			 }
        }

		if(ans) System.out.println("Yes");
		else System.out.println("No");

	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int[] a = new int[4]; a new int[4] 4 int[] b = new int[4]; b new int[4] 4 int[][] c = new int[4][4]; c new int[4][4] 4 4 for(int i=1;i<=3;i++) {
			for(int j=1; j<=3; j++) {
				c[i][j] = sc.nextInt();
			}
		} int i=1; int i=1; i 1 i<=3 i 3 i++ i++ i {
			for(int j=1; j<=3; j++) {
				c[i][j] = sc.nextInt();
			}
		} {
			for(int j=1; j<=3; j++) {
				c[i][j] = sc.nextInt();
			}
		} for(int j=1; j<=3; j++) {
				c[i][j] = sc.nextInt();
			} int j=1; int j=1; j 1 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 a[1] = c[1][1] a[1] a 1 c[1][1] c[1] c 1 1 a[2] = c[2][1] a[2] a 2 c[2][1] c[2] c 2 1 a[3] = c[3][1] a[3] a 3 c[3][1] c[3] c 3 1 b[1] = 0 b[1] b 1 0 b[2] = c[1][2] - c[1][1] b[2] b 2 c[1][2] - c[1][1] c[1][2] c[1] c 1 2 c[1][1] c[1] c 1 1 b[3] = c[1][3] - c[1][1] b[3] b 3 c[1][3] - c[1][1] c[1][3] c[1] c 1 3 c[1][1] c[1] c 1 1 boolean ans = true; ans true int numbers[] = {2,3}; numbers {2,3} 2 3 for (int i : numbers) {
			 for(int j: numbers) {
				 if(a[i] + b[j] == c[i][j]);
				 else ans = false;
			 }
        } int i numbers {
			 for(int j: numbers) {
				 if(a[i] + b[j] == c[i][j]);
				 else ans = false;
			 }
        } {
			 for(int j: numbers) {
				 if(a[i] + b[j] == c[i][j]);
				 else ans = false;
			 }
        } for(int j: numbers) {
				 if(a[i] + b[j] == c[i][j]);
				 else ans = false;
			 } int j numbers {
				 if(a[i] + b[j] == c[i][j]);
				 else ans = false;
			 } {
				 if(a[i] + b[j] == c[i][j]);
				 else ans = false;
			 } if(a[i] + b[j] == c[i][j]);
				 else ans = false; a[i] + b[j] == c[i][j] a[i] + b[j] a[i] a i b[j] b j c[i][j] c[i] c i j ans = false ans false if(ans) System.out.println("Yes");
		else System.out.println("No"); ans System.out.println("Yes") System.out.println System.out System System.out "Yes" 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[] a = new int[4];
		int[] b = new int[4];
		int[][] c = new int[4][4];
		for(int i=1;i<=3;i++) {
			for(int j=1; j<=3; j++) {
				c[i][j] = sc.nextInt();
			}
		}
		a[1] = c[1][1];
		a[2] = c[2][1];
		a[3] = c[3][1];
		b[1] = 0;
		b[2] = c[1][2] - c[1][1];
		b[3] = c[1][3] - c[1][1];

		boolean ans = true;
		int numbers[] = {2,3};//[1]
		 for (int i : numbers) {
			 for(int j: numbers) {
				 if(a[i] + b[j] == c[i][j]);
				 else ans = false;
			 }
        }

		if(ans) 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[] a = new int[4];
		int[] b = new int[4];
		int[][] c = new int[4][4];
		for(int i=1;i<=3;i++) {
			for(int j=1; j<=3; j++) {
				c[i][j] = sc.nextInt();
			}
		}
		a[1] = c[1][1];
		a[2] = c[2][1];
		a[3] = c[3][1];
		b[1] = 0;
		b[2] = c[1][2] - c[1][1];
		b[3] = c[1][3] - c[1][1];

		boolean ans = true;
		int numbers[] = {2,3};//[1]
		 for (int i : numbers) {
			 for(int j: numbers) {
				 if(a[i] + b[j] == c[i][j]);
				 else ans = false;
			 }
        }

		if(ans) 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[] a = new int[4];
		int[] b = new int[4];
		int[][] c = new int[4][4];
		for(int i=1;i<=3;i++) {
			for(int j=1; j<=3; j++) {
				c[i][j] = sc.nextInt();
			}
		}
		a[1] = c[1][1];
		a[2] = c[2][1];
		a[3] = c[3][1];
		b[1] = 0;
		b[2] = c[1][2] - c[1][1];
		b[3] = c[1][3] - c[1][1];

		boolean ans = true;
		int numbers[] = {2,3};//[1]
		 for (int i : numbers) {
			 for(int j: numbers) {
				 if(a[i] + b[j] == c[i][j]);
				 else ans = false;
			 }
        }

		if(ans) System.out.println("Yes");
		else System.out.println("No");

	}
}
