import java.util.Scanner;
 
public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
 		//座標で
        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[] x = new int[3];
        int[] y = new int[3];
      	//y[0] =c[0][0]-x[0]するため代入
        x[0] = 0;
        for(int i=0; i<3; i++) {
            y[i] = c[0][i] - x[0];
        }
        for(int i=0; i<3; i++) {
            x[i] = c[i][0] - y[0];
        }
 
        for(int i=0; i<3; i++) {
            for(int j=0; j<3; j++) {
                if(c[i][j] != x[i]+y[j]) {
                    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);
 		//座標で
        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[] x = new int[3];
        int[] y = new int[3];
      	//y[0] =c[0][0]-x[0]するため代入
        x[0] = 0;
        for(int i=0; i<3; i++) {
            y[i] = c[0][i] - x[0];
        }
        for(int i=0; i<3; i++) {
            x[i] = c[i][0] - y[0];
        }
 
        for(int i=0; i<3; i++) {
            for(int j=0; j<3; j++) {
                if(c[i][j] != x[i]+y[j]) {
                    System.out.println("No");
                    return;
                }
            }
        }
        System.out.println("Yes");
    }
} Main public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
 		//座標で
        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[] x = new int[3];
        int[] y = new int[3];
      	//y[0] =c[0][0]-x[0]するため代入
        x[0] = 0;
        for(int i=0; i<3; i++) {
            y[i] = c[0][i] - x[0];
        }
        for(int i=0; i<3; i++) {
            x[i] = c[i][0] - y[0];
        }
 
        for(int i=0; i<3; i++) {
            for(int j=0; j<3; j++) {
                if(c[i][j] != x[i]+y[j]) {
                    System.out.println("No");
                    return;
                }
            }
        }
        System.out.println("Yes");
    } main {
        Scanner sc = new Scanner(System.in);
 		//座標で
        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[] x = new int[3];
        int[] y = new int[3];
      	//y[0] =c[0][0]-x[0]するため代入
        x[0] = 0;
        for(int i=0; i<3; i++) {
            y[i] = c[0][i] - x[0];
        }
        for(int i=0; i<3; i++) {
            x[i] = c[i][0] - y[0];
        }
 
        for(int i=0; i<3; i++) {
            for(int j=0; j<3; j++) {
                if(c[i][j] != x[i]+y[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[] x = new int[3]; x new int[3] 3 int[] y = new int[3]; y new int[3] 3 x[0] = 0 x[0] x 0 0 for(int i=0; i<3; i++) {
            y[i] = c[0][i] - x[0];
        } int i=0; int i=0; i 0 i<3 i 3 i++ i++ i {
            y[i] = c[0][i] - x[0];
        } {
            y[i] = c[0][i] - x[0];
        } y[i] = c[0][i] - x[0] y[i] y i c[0][i] - x[0] c[0][i] c[0] c 0 i x[0] x 0 for(int i=0; i<3; i++) {
            x[i] = c[i][0] - y[0];
        } int i=0; int i=0; i 0 i<3 i 3 i++ i++ i {
            x[i] = c[i][0] - y[0];
        } {
            x[i] = c[i][0] - y[0];
        } x[i] = c[i][0] - y[0] x[i] x i c[i][0] - y[0] c[i][0] c[i] c i 0 y[0] y 0 for(int i=0; i<3; i++) {
            for(int j=0; j<3; j++) {
                if(c[i][j] != x[i]+y[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] != x[i]+y[j]) {
                    System.out.println("No");
                    return;
                }
            }
        } {
            for(int j=0; j<3; j++) {
                if(c[i][j] != x[i]+y[j]) {
                    System.out.println("No");
                    return;
                }
            }
        } for(int j=0; j<3; j++) {
                if(c[i][j] != x[i]+y[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] != x[i]+y[j]) {
                    System.out.println("No");
                    return;
                }
            } {
                if(c[i][j] != x[i]+y[j]) {
                    System.out.println("No");
                    return;
                }
            } if(c[i][j] != x[i]+y[j]) {
                    System.out.println("No");
                    return;
                } c[i][j] != x[i]+y[j] c[i][j] c[i] c i j x[i]+y[j] x[i] x i y[j] y 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);
 		//座標で
        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[] x = new int[3];
        int[] y = new int[3];
      	//y[0] =c[0][0]-x[0]するため代入
        x[0] = 0;
        for(int i=0; i<3; i++) {
            y[i] = c[0][i] - x[0];
        }
        for(int i=0; i<3; i++) {
            x[i] = c[i][0] - y[0];
        }
 
        for(int i=0; i<3; i++) {
            for(int j=0; j<3; j++) {
                if(c[i][j] != x[i]+y[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);
 		//座標で
        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[] x = new int[3];
        int[] y = new int[3];
      	//y[0] =c[0][0]-x[0]するため代入
        x[0] = 0;
        for(int i=0; i<3; i++) {
            y[i] = c[0][i] - x[0];
        }
        for(int i=0; i<3; i++) {
            x[i] = c[i][0] - y[0];
        }
 
        for(int i=0; i<3; i++) {
            for(int j=0; j<3; j++) {
                if(c[i][j] != x[i]+y[j]) {
                    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);
 		//座標で
        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[] x = new int[3];
        int[] y = new int[3];
      	//y[0] =c[0][0]-x[0]するため代入
        x[0] = 0;
        for(int i=0; i<3; i++) {
            y[i] = c[0][i] - x[0];
        }
        for(int i=0; i<3; i++) {
            x[i] = c[i][0] - y[0];
        }
 
        for(int i=0; i<3; i++) {
            for(int j=0; j<3; j++) {
                if(c[i][j] != x[i]+y[j]) {
                    System.out.println("No");
                    return;
                }
            }
        }
        System.out.println("Yes");
    }
}