import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Scanner;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 */
public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        TaskC solver = new TaskC();
        solver.solve(1, in, out);
        out.close();
    }

    static class TaskC {
        public void solve(int testNumber, Scanner in, PrintWriter out) {
            int[][] c = new int[3][3];
            for (int i = 0; i < 3; i++) for (int j = 0; j < 3; j++) c[i][j] = in.nextInt();
            int[] a = new int[3];
            int[] b = new int[3];
            a[0] = 0;
            b[0] = c[0][0] - a[0];
            b[1] = c[0][1] - a[0];
            b[2] = c[0][2] - a[0];
            a[1] = c[1][0] - b[0];
            a[2] = c[2][0] - b[0];

            String ans = "Yes";
            for (int i = 0; i < 3; i++) {
                for (int j = 0; j < 3; j++) {
                    if (c[i][j] != a[i] + b[j]) {
                        ans = "No";
                        break;
                    }
                }
            }

            out.println(ans);
        }

    }
}
 import java.io.OutputStream; OutputStream java.io import java.io.IOException; IOException java.io import java.io.InputStream; InputStream java.io import java.io.PrintWriter; PrintWriter java.io import java.util.Scanner; Scanner java.util public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        TaskC solver = new TaskC();
        solver.solve(1, in, out);
        out.close();
    }

    static class TaskC {
        public void solve(int testNumber, Scanner in, PrintWriter out) {
            int[][] c = new int[3][3];
            for (int i = 0; i < 3; i++) for (int j = 0; j < 3; j++) c[i][j] = in.nextInt();
            int[] a = new int[3];
            int[] b = new int[3];
            a[0] = 0;
            b[0] = c[0][0] - a[0];
            b[1] = c[0][1] - a[0];
            b[2] = c[0][2] - a[0];
            a[1] = c[1][0] - b[0];
            a[2] = c[2][0] - b[0];

            String ans = "Yes";
            for (int i = 0; i < 3; i++) {
                for (int j = 0; j < 3; j++) {
                    if (c[i][j] != a[i] + b[j]) {
                        ans = "No";
                        break;
                    }
                }
            }

            out.println(ans);
        }

    }
} Main public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        TaskC solver = new TaskC();
        solver.solve(1, in, out);
        out.close();
    } main {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        TaskC solver = new TaskC();
        solver.solve(1, in, out);
        out.close();
    } InputStream inputStream = System.in; inputStream System.in System System.in OutputStream outputStream = System.out; outputStream System.out System System.out Scanner in = new Scanner(inputStream); in new Scanner(inputStream) PrintWriter out = new PrintWriter(outputStream); out new PrintWriter(outputStream) TaskC solver = new TaskC(); solver new TaskC() solver.solve(1, in, out) solver.solve solver 1 in out out.close() out.close out String[] args args static class TaskC {
        public void solve(int testNumber, Scanner in, PrintWriter out) {
            int[][] c = new int[3][3];
            for (int i = 0; i < 3; i++) for (int j = 0; j < 3; j++) c[i][j] = in.nextInt();
            int[] a = new int[3];
            int[] b = new int[3];
            a[0] = 0;
            b[0] = c[0][0] - a[0];
            b[1] = c[0][1] - a[0];
            b[2] = c[0][2] - a[0];
            a[1] = c[1][0] - b[0];
            a[2] = c[2][0] - b[0];

            String ans = "Yes";
            for (int i = 0; i < 3; i++) {
                for (int j = 0; j < 3; j++) {
                    if (c[i][j] != a[i] + b[j]) {
                        ans = "No";
                        break;
                    }
                }
            }

            out.println(ans);
        }

    } TaskC public void solve(int testNumber, Scanner in, PrintWriter out) {
            int[][] c = new int[3][3];
            for (int i = 0; i < 3; i++) for (int j = 0; j < 3; j++) c[i][j] = in.nextInt();
            int[] a = new int[3];
            int[] b = new int[3];
            a[0] = 0;
            b[0] = c[0][0] - a[0];
            b[1] = c[0][1] - a[0];
            b[2] = c[0][2] - a[0];
            a[1] = c[1][0] - b[0];
            a[2] = c[2][0] - b[0];

            String ans = "Yes";
            for (int i = 0; i < 3; i++) {
                for (int j = 0; j < 3; j++) {
                    if (c[i][j] != a[i] + b[j]) {
                        ans = "No";
                        break;
                    }
                }
            }

            out.println(ans);
        } solve {
            int[][] c = new int[3][3];
            for (int i = 0; i < 3; i++) for (int j = 0; j < 3; j++) c[i][j] = in.nextInt();
            int[] a = new int[3];
            int[] b = new int[3];
            a[0] = 0;
            b[0] = c[0][0] - a[0];
            b[1] = c[0][1] - a[0];
            b[2] = c[0][2] - a[0];
            a[1] = c[1][0] - b[0];
            a[2] = c[2][0] - b[0];

            String ans = "Yes";
            for (int i = 0; i < 3; i++) {
                for (int j = 0; j < 3; j++) {
                    if (c[i][j] != a[i] + b[j]) {
                        ans = "No";
                        break;
                    }
                }
            }

            out.println(ans);
        } 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] = in.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] = in.nextInt(); for (int j = 0; j < 3; j++) c[i][j] = in.nextInt(); int j = 0; int j = 0; j 0 j < 3 j 3 j++ j++ j c[i][j] = in.nextInt(); c[i][j] = in.nextInt() c[i][j] c[i] c i j in.nextInt() in.nextInt in int[] a = new int[3]; a new int[3] 3 int[] b = new int[3]; b new int[3] 3 a[0] = 0 a[0] a 0 0 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] - a[0] b[2] b 2 c[0][2] - a[0] c[0][2] c[0] c 0 2 a[0] a 0 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][0] - b[0] a[2] a 2 c[2][0] - b[0] c[2][0] c[2] c 2 0 b[0] b 0 String ans = "Yes"; ans "Yes" for (int i = 0; i < 3; i++) {
                for (int j = 0; j < 3; j++) {
                    if (c[i][j] != a[i] + b[j]) {
                        ans = "No";
                        break;
                    }
                }
            } 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]) {
                        ans = "No";
                        break;
                    }
                }
            } {
                for (int j = 0; j < 3; j++) {
                    if (c[i][j] != a[i] + b[j]) {
                        ans = "No";
                        break;
                    }
                }
            } for (int j = 0; j < 3; j++) {
                    if (c[i][j] != a[i] + b[j]) {
                        ans = "No";
                        break;
                    }
                } int j = 0; int j = 0; j 0 j < 3 j 3 j++ j++ j {
                    if (c[i][j] != a[i] + b[j]) {
                        ans = "No";
                        break;
                    }
                } {
                    if (c[i][j] != a[i] + b[j]) {
                        ans = "No";
                        break;
                    }
                } if (c[i][j] != a[i] + b[j]) {
                        ans = "No";
                        break;
                    } 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 {
                        ans = "No";
                        break;
                    } ans = "No" ans "No" break; out.println(ans) out.println out ans int testNumber testNumber Scanner in in PrintWriter out out public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        TaskC solver = new TaskC();
        solver.solve(1, in, out);
        out.close();
    }

    static class TaskC {
        public void solve(int testNumber, Scanner in, PrintWriter out) {
            int[][] c = new int[3][3];
            for (int i = 0; i < 3; i++) for (int j = 0; j < 3; j++) c[i][j] = in.nextInt();
            int[] a = new int[3];
            int[] b = new int[3];
            a[0] = 0;
            b[0] = c[0][0] - a[0];
            b[1] = c[0][1] - a[0];
            b[2] = c[0][2] - a[0];
            a[1] = c[1][0] - b[0];
            a[2] = c[2][0] - b[0];

            String ans = "Yes";
            for (int i = 0; i < 3; i++) {
                for (int j = 0; j < 3; j++) {
                    if (c[i][j] != a[i] + b[j]) {
                        ans = "No";
                        break;
                    }
                }
            }

            out.println(ans);
        }

    }
} public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        TaskC solver = new TaskC();
        solver.solve(1, in, out);
        out.close();
    }

    static class TaskC {
        public void solve(int testNumber, Scanner in, PrintWriter out) {
            int[][] c = new int[3][3];
            for (int i = 0; i < 3; i++) for (int j = 0; j < 3; j++) c[i][j] = in.nextInt();
            int[] a = new int[3];
            int[] b = new int[3];
            a[0] = 0;
            b[0] = c[0][0] - a[0];
            b[1] = c[0][1] - a[0];
            b[2] = c[0][2] - a[0];
            a[1] = c[1][0] - b[0];
            a[2] = c[2][0] - b[0];

            String ans = "Yes";
            for (int i = 0; i < 3; i++) {
                for (int j = 0; j < 3; j++) {
                    if (c[i][j] != a[i] + b[j]) {
                        ans = "No";
                        break;
                    }
                }
            }

            out.println(ans);
        }

    }
} Main
import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Scanner;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 */
public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        TaskC solver = new TaskC();
        solver.solve(1, in, out);
        out.close();
    }

    static class TaskC {
        public void solve(int testNumber, Scanner in, PrintWriter out) {
            int[][] c = new int[3][3];
            for (int i = 0; i < 3; i++) for (int j = 0; j < 3; j++) c[i][j] = in.nextInt();
            int[] a = new int[3];
            int[] b = new int[3];
            a[0] = 0;
            b[0] = c[0][0] - a[0];
            b[1] = c[0][1] - a[0];
            b[2] = c[0][2] - a[0];
            a[1] = c[1][0] - b[0];
            a[2] = c[2][0] - b[0];

            String ans = "Yes";
            for (int i = 0; i < 3; i++) {
                for (int j = 0; j < 3; j++) {
                    if (c[i][j] != a[i] + b[j]) {
                        ans = "No";
                        break;
                    }
                }
            }

            out.println(ans);
        }

    }
}

