import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.StringTokenizer;
import java.io.IOException;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.InputStream;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 *
 * @author palayutm
 */
public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(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, InputReader in, PrintWriter out) {
            int[][] a = in.nextInt2dArray(3, 3);
            for (int i = 1; i < 3; i++) {
                for (int j = 0; j < 3; j++) {
                    if (a[i][j] - a[i - 1][j] != a[i][0] - a[i - 1][0]) {
                        out.println("No");
                        return;
                    }
                }
            }
            for (int j = 1; j < 3; j++) {
                for (int i = 0; i < 3; i++) {
                    if (a[i][j] - a[i][j - 1] != a[0][j] - a[0][j - 1]) {
                        out.println("No");
                        return;
                    }
                }
            }
            out.println("Yes");
        }

    }

    static class InputReader {
        public BufferedReader reader;
        public StringTokenizer tokenizer;

        public InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        }

        public String next() {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        }

        public int nextInt() {
            return Integer.parseInt(next());
        }

        public int[][] nextInt2dArray(int n, int m) {
            int[][] a = new int[n][m];
            for (int i = 0; i < n; i++) {
                for (int j = 0; j < m; j++) {
                    a[i][j] = nextInt();
                }
            }
            return a;
        }

    }
}
 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.StringTokenizer; StringTokenizer java.util import java.io.IOException; IOException java.io import java.io.BufferedReader; BufferedReader java.io import java.io.InputStreamReader; InputStreamReader java.io import java.io.InputStream; InputStream java.io public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(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, InputReader in, PrintWriter out) {
            int[][] a = in.nextInt2dArray(3, 3);
            for (int i = 1; i < 3; i++) {
                for (int j = 0; j < 3; j++) {
                    if (a[i][j] - a[i - 1][j] != a[i][0] - a[i - 1][0]) {
                        out.println("No");
                        return;
                    }
                }
            }
            for (int j = 1; j < 3; j++) {
                for (int i = 0; i < 3; i++) {
                    if (a[i][j] - a[i][j - 1] != a[0][j] - a[0][j - 1]) {
                        out.println("No");
                        return;
                    }
                }
            }
            out.println("Yes");
        }

    }

    static class InputReader {
        public BufferedReader reader;
        public StringTokenizer tokenizer;

        public InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        }

        public String next() {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        }

        public int nextInt() {
            return Integer.parseInt(next());
        }

        public int[][] nextInt2dArray(int n, int m) {
            int[][] a = new int[n][m];
            for (int i = 0; i < n; i++) {
                for (int j = 0; j < m; j++) {
                    a[i][j] = nextInt();
                }
            }
            return a;
        }

    }
} Main public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(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;
        InputReader in = new InputReader(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 InputReader in = new InputReader(inputStream); in new InputReader(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, InputReader in, PrintWriter out) {
            int[][] a = in.nextInt2dArray(3, 3);
            for (int i = 1; i < 3; i++) {
                for (int j = 0; j < 3; j++) {
                    if (a[i][j] - a[i - 1][j] != a[i][0] - a[i - 1][0]) {
                        out.println("No");
                        return;
                    }
                }
            }
            for (int j = 1; j < 3; j++) {
                for (int i = 0; i < 3; i++) {
                    if (a[i][j] - a[i][j - 1] != a[0][j] - a[0][j - 1]) {
                        out.println("No");
                        return;
                    }
                }
            }
            out.println("Yes");
        }

    } TaskC public void solve(int testNumber, InputReader in, PrintWriter out) {
            int[][] a = in.nextInt2dArray(3, 3);
            for (int i = 1; i < 3; i++) {
                for (int j = 0; j < 3; j++) {
                    if (a[i][j] - a[i - 1][j] != a[i][0] - a[i - 1][0]) {
                        out.println("No");
                        return;
                    }
                }
            }
            for (int j = 1; j < 3; j++) {
                for (int i = 0; i < 3; i++) {
                    if (a[i][j] - a[i][j - 1] != a[0][j] - a[0][j - 1]) {
                        out.println("No");
                        return;
                    }
                }
            }
            out.println("Yes");
        } solve {
            int[][] a = in.nextInt2dArray(3, 3);
            for (int i = 1; i < 3; i++) {
                for (int j = 0; j < 3; j++) {
                    if (a[i][j] - a[i - 1][j] != a[i][0] - a[i - 1][0]) {
                        out.println("No");
                        return;
                    }
                }
            }
            for (int j = 1; j < 3; j++) {
                for (int i = 0; i < 3; i++) {
                    if (a[i][j] - a[i][j - 1] != a[0][j] - a[0][j - 1]) {
                        out.println("No");
                        return;
                    }
                }
            }
            out.println("Yes");
        } int[][] a = in.nextInt2dArray(3, 3); a in.nextInt2dArray(3, 3) in.nextInt2dArray in 3 3 for (int i = 1; i < 3; i++) {
                for (int j = 0; j < 3; j++) {
                    if (a[i][j] - a[i - 1][j] != a[i][0] - a[i - 1][0]) {
                        out.println("No");
                        return;
                    }
                }
            } int i = 1; int i = 1; i 1 i < 3 i 3 i++ i++ i {
                for (int j = 0; j < 3; j++) {
                    if (a[i][j] - a[i - 1][j] != a[i][0] - a[i - 1][0]) {
                        out.println("No");
                        return;
                    }
                }
            } {
                for (int j = 0; j < 3; j++) {
                    if (a[i][j] - a[i - 1][j] != a[i][0] - a[i - 1][0]) {
                        out.println("No");
                        return;
                    }
                }
            } for (int j = 0; j < 3; j++) {
                    if (a[i][j] - a[i - 1][j] != a[i][0] - a[i - 1][0]) {
                        out.println("No");
                        return;
                    }
                } int j = 0; int j = 0; j 0 j < 3 j 3 j++ j++ j {
                    if (a[i][j] - a[i - 1][j] != a[i][0] - a[i - 1][0]) {
                        out.println("No");
                        return;
                    }
                } {
                    if (a[i][j] - a[i - 1][j] != a[i][0] - a[i - 1][0]) {
                        out.println("No");
                        return;
                    }
                } if (a[i][j] - a[i - 1][j] != a[i][0] - a[i - 1][0]) {
                        out.println("No");
                        return;
                    } a[i][j] - a[i - 1][j] != a[i][0] - a[i - 1][0] a[i][j] - a[i - 1][j] a[i][j] a[i] a i j a[i - 1][j] a[i - 1] a i - 1 i 1 j a[i][0] - a[i - 1][0] a[i][0] a[i] a i 0 a[i - 1][0] a[i - 1] a i - 1 i 1 0 {
                        out.println("No");
                        return;
                    } out.println("No") out.println out "No" return; for (int j = 1; j < 3; j++) {
                for (int i = 0; i < 3; i++) {
                    if (a[i][j] - a[i][j - 1] != a[0][j] - a[0][j - 1]) {
                        out.println("No");
                        return;
                    }
                }
            } int j = 1; int j = 1; j 1 j < 3 j 3 j++ j++ j {
                for (int i = 0; i < 3; i++) {
                    if (a[i][j] - a[i][j - 1] != a[0][j] - a[0][j - 1]) {
                        out.println("No");
                        return;
                    }
                }
            } {
                for (int i = 0; i < 3; i++) {
                    if (a[i][j] - a[i][j - 1] != a[0][j] - a[0][j - 1]) {
                        out.println("No");
                        return;
                    }
                }
            } for (int i = 0; i < 3; i++) {
                    if (a[i][j] - a[i][j - 1] != a[0][j] - a[0][j - 1]) {
                        out.println("No");
                        return;
                    }
                } int i = 0; int i = 0; i 0 i < 3 i 3 i++ i++ i {
                    if (a[i][j] - a[i][j - 1] != a[0][j] - a[0][j - 1]) {
                        out.println("No");
                        return;
                    }
                } {
                    if (a[i][j] - a[i][j - 1] != a[0][j] - a[0][j - 1]) {
                        out.println("No");
                        return;
                    }
                } if (a[i][j] - a[i][j - 1] != a[0][j] - a[0][j - 1]) {
                        out.println("No");
                        return;
                    } a[i][j] - a[i][j - 1] != a[0][j] - a[0][j - 1] a[i][j] - a[i][j - 1] a[i][j] a[i] a i j a[i][j - 1] a[i] a i j - 1 j 1 a[0][j] - a[0][j - 1] a[0][j] a[0] a 0 j a[0][j - 1] a[0] a 0 j - 1 j 1 {
                        out.println("No");
                        return;
                    } out.println("No") out.println out "No" return; out.println("Yes") out.println out "Yes" int testNumber testNumber InputReader in in PrintWriter out out static class InputReader {
        public BufferedReader reader;
        public StringTokenizer tokenizer;

        public InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        }

        public String next() {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        }

        public int nextInt() {
            return Integer.parseInt(next());
        }

        public int[][] nextInt2dArray(int n, int m) {
            int[][] a = new int[n][m];
            for (int i = 0; i < n; i++) {
                for (int j = 0; j < m; j++) {
                    a[i][j] = nextInt();
                }
            }
            return a;
        }

    } InputReader public BufferedReader reader; reader public StringTokenizer tokenizer; tokenizer public InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        } InputReader {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        } reader = new BufferedReader(new InputStreamReader(stream), 32768) reader new BufferedReader(new InputStreamReader(stream), 32768) tokenizer = null tokenizer null InputStream stream stream public String next() {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        } next {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        } while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            } tokenizer == null || !tokenizer.hasMoreTokens() tokenizer == null tokenizer null !tokenizer.hasMoreTokens() tokenizer.hasMoreTokens() tokenizer.hasMoreTokens tokenizer {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            } try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                } catch (IOException e) {
                    throw new RuntimeException(e);
                } IOException e {
                    throw new RuntimeException(e);
                } throw new RuntimeException(e); new RuntimeException(e) {
                    tokenizer = new StringTokenizer(reader.readLine());
                } tokenizer = new StringTokenizer(reader.readLine()) tokenizer new StringTokenizer(reader.readLine()) return tokenizer.nextToken(); tokenizer.nextToken() tokenizer.nextToken tokenizer public int nextInt() {
            return Integer.parseInt(next());
        } nextInt {
            return Integer.parseInt(next());
        } return Integer.parseInt(next()); Integer.parseInt(next()) Integer.parseInt Integer next() next public int[][] nextInt2dArray(int n, int m) {
            int[][] a = new int[n][m];
            for (int i = 0; i < n; i++) {
                for (int j = 0; j < m; j++) {
                    a[i][j] = nextInt();
                }
            }
            return a;
        } nextInt2dArray {
            int[][] a = new int[n][m];
            for (int i = 0; i < n; i++) {
                for (int j = 0; j < m; j++) {
                    a[i][j] = nextInt();
                }
            }
            return a;
        } int[][] a = new int[n][m]; a new int[n][m] n m for (int i = 0; i < n; i++) {
                for (int j = 0; j < m; j++) {
                    a[i][j] = nextInt();
                }
            } int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
                for (int j = 0; j < m; j++) {
                    a[i][j] = nextInt();
                }
            } {
                for (int j = 0; j < m; j++) {
                    a[i][j] = nextInt();
                }
            } for (int j = 0; j < m; j++) {
                    a[i][j] = nextInt();
                } int j = 0; int j = 0; j 0 j < m j m j++ j++ j {
                    a[i][j] = nextInt();
                } {
                    a[i][j] = nextInt();
                } a[i][j] = nextInt() a[i][j] a[i] a i j nextInt() nextInt return a; a int n n int m m public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(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, InputReader in, PrintWriter out) {
            int[][] a = in.nextInt2dArray(3, 3);
            for (int i = 1; i < 3; i++) {
                for (int j = 0; j < 3; j++) {
                    if (a[i][j] - a[i - 1][j] != a[i][0] - a[i - 1][0]) {
                        out.println("No");
                        return;
                    }
                }
            }
            for (int j = 1; j < 3; j++) {
                for (int i = 0; i < 3; i++) {
                    if (a[i][j] - a[i][j - 1] != a[0][j] - a[0][j - 1]) {
                        out.println("No");
                        return;
                    }
                }
            }
            out.println("Yes");
        }

    }

    static class InputReader {
        public BufferedReader reader;
        public StringTokenizer tokenizer;

        public InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        }

        public String next() {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        }

        public int nextInt() {
            return Integer.parseInt(next());
        }

        public int[][] nextInt2dArray(int n, int m) {
            int[][] a = new int[n][m];
            for (int i = 0; i < n; i++) {
                for (int j = 0; j < m; j++) {
                    a[i][j] = nextInt();
                }
            }
            return a;
        }

    }
} public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(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, InputReader in, PrintWriter out) {
            int[][] a = in.nextInt2dArray(3, 3);
            for (int i = 1; i < 3; i++) {
                for (int j = 0; j < 3; j++) {
                    if (a[i][j] - a[i - 1][j] != a[i][0] - a[i - 1][0]) {
                        out.println("No");
                        return;
                    }
                }
            }
            for (int j = 1; j < 3; j++) {
                for (int i = 0; i < 3; i++) {
                    if (a[i][j] - a[i][j - 1] != a[0][j] - a[0][j - 1]) {
                        out.println("No");
                        return;
                    }
                }
            }
            out.println("Yes");
        }

    }

    static class InputReader {
        public BufferedReader reader;
        public StringTokenizer tokenizer;

        public InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        }

        public String next() {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        }

        public int nextInt() {
            return Integer.parseInt(next());
        }

        public int[][] nextInt2dArray(int n, int m) {
            int[][] a = new int[n][m];
            for (int i = 0; i < n; i++) {
                for (int j = 0; j < m; j++) {
                    a[i][j] = nextInt();
                }
            }
            return a;
        }

    }
} Main
import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.StringTokenizer;
import java.io.IOException;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.InputStream;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 *
 * @author palayutm
 */
public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(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, InputReader in, PrintWriter out) {
            int[][] a = in.nextInt2dArray(3, 3);
            for (int i = 1; i < 3; i++) {
                for (int j = 0; j < 3; j++) {
                    if (a[i][j] - a[i - 1][j] != a[i][0] - a[i - 1][0]) {
                        out.println("No");
                        return;
                    }
                }
            }
            for (int j = 1; j < 3; j++) {
                for (int i = 0; i < 3; i++) {
                    if (a[i][j] - a[i][j - 1] != a[0][j] - a[0][j - 1]) {
                        out.println("No");
                        return;
                    }
                }
            }
            out.println("Yes");
        }

    }

    static class InputReader {
        public BufferedReader reader;
        public StringTokenizer tokenizer;

        public InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        }

        public String next() {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        }

        public int nextInt() {
            return Integer.parseInt(next());
        }

        public int[][] nextInt2dArray(int n, int m) {
            int[][] a = new int[n][m];
            for (int i = 0; i < n; i++) {
                for (int j = 0; j < m; j++) {
                    a[i][j] = nextInt();
                }
            }
            return a;
        }

    }
}

