import java.util.Scanner;

class Main {
	int[][] c;

	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		Main m = new Main(sc);
		m.solve();
		sc.close();
	}
	Main(Scanner sc){
		c = new int[3][3];
		for(int i=0;i<3;i++){
			for(int j=0;j<3;j++){
				c[i][j] = sc.nextInt();
			}
		}
	}
	void solve(){
		int[] a = new int[3];
		int[] b = new int[3];
		int min = Math.min(c[0][0], Math.min(c[0][1], c[0][2]));
		for(int i=0;i<=min;i++){
			a[0] = i;b[0] = c[0][0] - a[0];b[1] = c[0][1] - a[0];b[2] = c[0][2];
			a[1] = c[1][0] - b[0];a[2] = c[2][1] - b[1];
			//System.out.printf("a1=%-2d a2=%-2d a3=%-2d b1=%-2d b2=%-2d b3=%-2d\n",a[0],a[1],a[2],b[0],b[1],b[2]);
			check:for(int j=0;j<3;j++){
				for(int k=0;k<3;k++){
					if(c[j][k]!=a[j]+b[k]) break check;
					if(j==2&&k==2){
						System.out.println("Yes");
						System.exit(0);
					}
				}
			}
		}
		System.out.println("No");
	}
} import java.util.Scanner; Scanner java.util class Main {
	int[][] c;

	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		Main m = new Main(sc);
		m.solve();
		sc.close();
	}
	Main(Scanner sc){
		c = new int[3][3];
		for(int i=0;i<3;i++){
			for(int j=0;j<3;j++){
				c[i][j] = sc.nextInt();
			}
		}
	}
	void solve(){
		int[] a = new int[3];
		int[] b = new int[3];
		int min = Math.min(c[0][0], Math.min(c[0][1], c[0][2]));
		for(int i=0;i<=min;i++){
			a[0] = i;b[0] = c[0][0] - a[0];b[1] = c[0][1] - a[0];b[2] = c[0][2];
			a[1] = c[1][0] - b[0];a[2] = c[2][1] - b[1];
			//System.out.printf("a1=%-2d a2=%-2d a3=%-2d b1=%-2d b2=%-2d b3=%-2d\n",a[0],a[1],a[2],b[0],b[1],b[2]);
			check:for(int j=0;j<3;j++){
				for(int k=0;k<3;k++){
					if(c[j][k]!=a[j]+b[k]) break check;
					if(j==2&&k==2){
						System.out.println("Yes");
						System.exit(0);
					}
				}
			}
		}
		System.out.println("No");
	}
} Main int[][] c; c public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		Main m = new Main(sc);
		m.solve();
		sc.close();
	} main {
		Scanner sc = new Scanner(System.in);
		Main m = new Main(sc);
		m.solve();
		sc.close();
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) Main m = new Main(sc); m new Main(sc) m.solve() m.solve m sc.close() sc.close sc String[] args args Main(Scanner sc){
		c = new int[3][3];
		for(int i=0;i<3;i++){
			for(int j=0;j<3;j++){
				c[i][j] = sc.nextInt();
			}
		}
	} Main {
		c = new int[3][3];
		for(int i=0;i<3;i++){
			for(int j=0;j<3;j++){
				c[i][j] = sc.nextInt();
			}
		}
	} 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 Scanner sc sc void solve(){
		int[] a = new int[3];
		int[] b = new int[3];
		int min = Math.min(c[0][0], Math.min(c[0][1], c[0][2]));
		for(int i=0;i<=min;i++){
			a[0] = i;b[0] = c[0][0] - a[0];b[1] = c[0][1] - a[0];b[2] = c[0][2];
			a[1] = c[1][0] - b[0];a[2] = c[2][1] - b[1];
			//System.out.printf("a1=%-2d a2=%-2d a3=%-2d b1=%-2d b2=%-2d b3=%-2d\n",a[0],a[1],a[2],b[0],b[1],b[2]);
			check:for(int j=0;j<3;j++){
				for(int k=0;k<3;k++){
					if(c[j][k]!=a[j]+b[k]) break check;
					if(j==2&&k==2){
						System.out.println("Yes");
						System.exit(0);
					}
				}
			}
		}
		System.out.println("No");
	} solve {
		int[] a = new int[3];
		int[] b = new int[3];
		int min = Math.min(c[0][0], Math.min(c[0][1], c[0][2]));
		for(int i=0;i<=min;i++){
			a[0] = i;b[0] = c[0][0] - a[0];b[1] = c[0][1] - a[0];b[2] = c[0][2];
			a[1] = c[1][0] - b[0];a[2] = c[2][1] - b[1];
			//System.out.printf("a1=%-2d a2=%-2d a3=%-2d b1=%-2d b2=%-2d b3=%-2d\n",a[0],a[1],a[2],b[0],b[1],b[2]);
			check:for(int j=0;j<3;j++){
				for(int k=0;k<3;k++){
					if(c[j][k]!=a[j]+b[k]) break check;
					if(j==2&&k==2){
						System.out.println("Yes");
						System.exit(0);
					}
				}
			}
		}
		System.out.println("No");
	} int[] a = new int[3]; a new int[3] 3 int[] b = new int[3]; b new int[3] 3 int min = Math.min(c[0][0], Math.min(c[0][1], c[0][2])); min Math.min(c[0][0], Math.min(c[0][1], c[0][2])) Math.min Math c[0][0] c[0] c 0 0 Math.min(c[0][1], c[0][2]) Math.min Math c[0][1] c[0] c 0 1 c[0][2] c[0] c 0 2 for(int i=0;i<=min;i++){
			a[0] = i;b[0] = c[0][0] - a[0];b[1] = c[0][1] - a[0];b[2] = c[0][2];
			a[1] = c[1][0] - b[0];a[2] = c[2][1] - b[1];
			//System.out.printf("a1=%-2d a2=%-2d a3=%-2d b1=%-2d b2=%-2d b3=%-2d\n",a[0],a[1],a[2],b[0],b[1],b[2]);
			check:for(int j=0;j<3;j++){
				for(int k=0;k<3;k++){
					if(c[j][k]!=a[j]+b[k]) break check;
					if(j==2&&k==2){
						System.out.println("Yes");
						System.exit(0);
					}
				}
			}
		} int i=0; int i=0; i 0 i<=min i min i++ i++ i {
			a[0] = i;b[0] = c[0][0] - a[0];b[1] = c[0][1] - a[0];b[2] = c[0][2];
			a[1] = c[1][0] - b[0];a[2] = c[2][1] - b[1];
			//System.out.printf("a1=%-2d a2=%-2d a3=%-2d b1=%-2d b2=%-2d b3=%-2d\n",a[0],a[1],a[2],b[0],b[1],b[2]);
			check:for(int j=0;j<3;j++){
				for(int k=0;k<3;k++){
					if(c[j][k]!=a[j]+b[k]) break check;
					if(j==2&&k==2){
						System.out.println("Yes");
						System.exit(0);
					}
				}
			}
		} {
			a[0] = i;b[0] = c[0][0] - a[0];b[1] = c[0][1] - a[0];b[2] = c[0][2];
			a[1] = c[1][0] - b[0];a[2] = c[2][1] - b[1];
			//System.out.printf("a1=%-2d a2=%-2d a3=%-2d b1=%-2d b2=%-2d b3=%-2d\n",a[0],a[1],a[2],b[0],b[1],b[2]);
			check:for(int j=0;j<3;j++){
				for(int k=0;k<3;k++){
					if(c[j][k]!=a[j]+b[k]) break check;
					if(j==2&&k==2){
						System.out.println("Yes");
						System.exit(0);
					}
				}
			}
		} a[0] = i a[0] a 0 i b[0] = c[0][0] - a[0] b[0] b 0 c[0][0] - a[0] c[0][0] c[0] c 0 0 a[0] a 0 b[1] = c[0][1] - a[0] b[1] b 1 c[0][1] - a[0] c[0][1] c[0] c 0 1 a[0] a 0 b[2] = c[0][2] b[2] b 2 c[0][2] c[0] c 0 2 a[1] = c[1][0] - b[0] a[1] a 1 c[1][0] - b[0] c[1][0] c[1] c 1 0 b[0] b 0 a[2] = c[2][1] - b[1] a[2] a 2 c[2][1] - b[1] c[2][1] c[2] c 2 1 b[1] b 1 System.out.println("No") System.out.println System.out System System.out "No"
import java.util.Scanner;

class Main {
	int[][] c;

	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		Main m = new Main(sc);
		m.solve();
		sc.close();
	}
	Main(Scanner sc){
		c = new int[3][3];
		for(int i=0;i<3;i++){
			for(int j=0;j<3;j++){
				c[i][j] = sc.nextInt();
			}
		}
	}
	void solve(){
		int[] a = new int[3];
		int[] b = new int[3];
		int min = Math.min(c[0][0], Math.min(c[0][1], c[0][2]));
		for(int i=0;i<=min;i++){
			a[0] = i;b[0] = c[0][0] - a[0];b[1] = c[0][1] - a[0];b[2] = c[0][2];
			a[1] = c[1][0] - b[0];a[2] = c[2][1] - b[1];
			//System.out.printf("a1=%-2d a2=%-2d a3=%-2d b1=%-2d b2=%-2d b3=%-2d\n",a[0],a[1],a[2],b[0],b[1],b[2]);
			check:for(int j=0;j<3;j++){
				for(int k=0;k<3;k++){
					if(c[j][k]!=a[j]+b[k]) break check;
					if(j==2&&k==2){
						System.out.println("Yes");
						System.exit(0);
					}
				}
			}
		}
		System.out.println("No");
	}
}