
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.StringTokenizer;

public class Main {
    int[][] css;

    public static void main(String args[]) {
        new Main().run();
    }

    void run() {
        FastReader sc = new FastReader();
        css = new int[3][3];
        for (int i = 0; i < 3; i++) {
            for (int j = 0; j < 3; j++) {
                css[i][j] = sc.nextInt();
            }
        }
        solve();
    }

    void solve() {
        boolean flag = true;
        if (!(css[0][0] - css[0][1] == css[1][0] - css[1][1] &&
                css[1][0] - css[1][1] == css[2][0] - css[2][1])) {
            flag = false;
        } else if (!(css[0][1] - css[0][2] == css[1][1] - css[1][2] &&
                css[1][1] - css[1][2] == css[2][1] - css[2][2])) {
            flag = false;
        }
        if (flag) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }
    }

    static class FastReader {
        BufferedReader br;
        StringTokenizer st;

        public FastReader() {
            br = new BufferedReader(new
                    InputStreamReader(System.in));
        }

        String next() {
            while (st == null || !st.hasMoreElements())
            {
                try
                {
                    st = new StringTokenizer(br.readLine());
                }
                catch (IOException e)
                {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }

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

        long nextLong()
        {
            return Long.parseLong(next());
        }

        double nextDouble()
        {
            return Double.parseDouble(next());
        }

        String nextLine() {
            String str = "";
            try
            {
                str = br.readLine();
            }
            catch (IOException e)
            {
                e.printStackTrace();
            }
            return str;
        }
    }
} import java.io.BufferedReader; BufferedReader java.io import java.io.IOException; IOException java.io import java.io.InputStreamReader; InputStreamReader java.io import java.util.StringTokenizer; StringTokenizer java.util public class Main {
    int[][] css;

    public static void main(String args[]) {
        new Main().run();
    }

    void run() {
        FastReader sc = new FastReader();
        css = new int[3][3];
        for (int i = 0; i < 3; i++) {
            for (int j = 0; j < 3; j++) {
                css[i][j] = sc.nextInt();
            }
        }
        solve();
    }

    void solve() {
        boolean flag = true;
        if (!(css[0][0] - css[0][1] == css[1][0] - css[1][1] &&
                css[1][0] - css[1][1] == css[2][0] - css[2][1])) {
            flag = false;
        } else if (!(css[0][1] - css[0][2] == css[1][1] - css[1][2] &&
                css[1][1] - css[1][2] == css[2][1] - css[2][2])) {
            flag = false;
        }
        if (flag) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }
    }

    static class FastReader {
        BufferedReader br;
        StringTokenizer st;

        public FastReader() {
            br = new BufferedReader(new
                    InputStreamReader(System.in));
        }

        String next() {
            while (st == null || !st.hasMoreElements())
            {
                try
                {
                    st = new StringTokenizer(br.readLine());
                }
                catch (IOException e)
                {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }

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

        long nextLong()
        {
            return Long.parseLong(next());
        }

        double nextDouble()
        {
            return Double.parseDouble(next());
        }

        String nextLine() {
            String str = "";
            try
            {
                str = br.readLine();
            }
            catch (IOException e)
            {
                e.printStackTrace();
            }
            return str;
        }
    }
} Main int[][] css; css public static void main(String args[]) {
        new Main().run();
    } main {
        new Main().run();
    } new Main().run() new Main().run new Main() String args[] args void run() {
        FastReader sc = new FastReader();
        css = new int[3][3];
        for (int i = 0; i < 3; i++) {
            for (int j = 0; j < 3; j++) {
                css[i][j] = sc.nextInt();
            }
        }
        solve();
    } run {
        FastReader sc = new FastReader();
        css = new int[3][3];
        for (int i = 0; i < 3; i++) {
            for (int j = 0; j < 3; j++) {
                css[i][j] = sc.nextInt();
            }
        }
        solve();
    } FastReader sc = new FastReader(); sc new FastReader() css = new int[3][3] css new int[3][3] 3 3 for (int i = 0; i < 3; i++) {
            for (int j = 0; j < 3; j++) {
                css[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++) {
                css[i][j] = sc.nextInt();
            }
        } {
            for (int j = 0; j < 3; j++) {
                css[i][j] = sc.nextInt();
            }
        } for (int j = 0; j < 3; j++) {
                css[i][j] = sc.nextInt();
            } int j = 0; int j = 0; j 0 j < 3 j 3 j++ j++ j {
                css[i][j] = sc.nextInt();
            } {
                css[i][j] = sc.nextInt();
            } css[i][j] = sc.nextInt() css[i][j] css[i] css i j sc.nextInt() sc.nextInt sc solve() solve void solve() {
        boolean flag = true;
        if (!(css[0][0] - css[0][1] == css[1][0] - css[1][1] &&
                css[1][0] - css[1][1] == css[2][0] - css[2][1])) {
            flag = false;
        } else if (!(css[0][1] - css[0][2] == css[1][1] - css[1][2] &&
                css[1][1] - css[1][2] == css[2][1] - css[2][2])) {
            flag = false;
        }
        if (flag) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }
    } solve {
        boolean flag = true;
        if (!(css[0][0] - css[0][1] == css[1][0] - css[1][1] &&
                css[1][0] - css[1][1] == css[2][0] - css[2][1])) {
            flag = false;
        } else if (!(css[0][1] - css[0][2] == css[1][1] - css[1][2] &&
                css[1][1] - css[1][2] == css[2][1] - css[2][2])) {
            flag = false;
        }
        if (flag) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }
    } boolean flag = true; flag true if (!(css[0][0] - css[0][1] == css[1][0] - css[1][1] &&
                css[1][0] - css[1][1] == css[2][0] - css[2][1])) {
            flag = false;
        } else if (!(css[0][1] - css[0][2] == css[1][1] - css[1][2] &&
                css[1][1] - css[1][2] == css[2][1] - css[2][2])) {
            flag = false;
        } !(css[0][0] - css[0][1] == css[1][0] - css[1][1] &&
                css[1][0] - css[1][1] == css[2][0] - css[2][1]) (css[0][0] - css[0][1] == css[1][0] - css[1][1] &&
                css[1][0] - css[1][1] == css[2][0] - css[2][1]) css[0][0] - css[0][1] == css[1][0] - css[1][1] css[0][0] - css[0][1] css[0][0] css[0] css 0 0 css[0][1] css[0] css 0 1 css[1][0] - css[1][1] css[1][0] css[1] css 1 0 css[1][1] css[1] css 1 1 css[1][0] - css[1][1] == css[2][0] - css[2][1] css[1][0] - css[1][1] css[1][0] css[1] css 1 0 css[1][1] css[1] css 1 1 css[2][0] - css[2][1] css[2][0] css[2] css 2 0 css[2][1] css[2] css 2 1 {
            flag = false;
        } flag = false flag false if (!(css[0][1] - css[0][2] == css[1][1] - css[1][2] &&
                css[1][1] - css[1][2] == css[2][1] - css[2][2])) {
            flag = false;
        } !(css[0][1] - css[0][2] == css[1][1] - css[1][2] &&
                css[1][1] - css[1][2] == css[2][1] - css[2][2]) (css[0][1] - css[0][2] == css[1][1] - css[1][2] &&
                css[1][1] - css[1][2] == css[2][1] - css[2][2]) css[0][1] - css[0][2] == css[1][1] - css[1][2] css[0][1] - css[0][2] css[0][1] css[0] css 0 1 css[0][2] css[0] css 0 2 css[1][1] - css[1][2] css[1][1] css[1] css 1 1 css[1][2] css[1] css 1 2 css[1][1] - css[1][2] == css[2][1] - css[2][2] css[1][1] - css[1][2] css[1][1] css[1] css 1 1 css[1][2] css[1] css 1 2 css[2][1] - css[2][2] css[2][1] css[2] css 2 1 css[2][2] css[2] css 2 2 {
            flag = false;
        } flag = false flag false if (flag) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        } flag {
            System.out.println("Yes");
        } System.out.println("Yes") System.out.println System.out System System.out "Yes" {
            System.out.println("No");
        } System.out.println("No") System.out.println System.out System System.out "No" static class FastReader {
        BufferedReader br;
        StringTokenizer st;

        public FastReader() {
            br = new BufferedReader(new
                    InputStreamReader(System.in));
        }

        String next() {
            while (st == null || !st.hasMoreElements())
            {
                try
                {
                    st = new StringTokenizer(br.readLine());
                }
                catch (IOException e)
                {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }

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

        long nextLong()
        {
            return Long.parseLong(next());
        }

        double nextDouble()
        {
            return Double.parseDouble(next());
        }

        String nextLine() {
            String str = "";
            try
            {
                str = br.readLine();
            }
            catch (IOException e)
            {
                e.printStackTrace();
            }
            return str;
        }
    } FastReader BufferedReader br; br StringTokenizer st; st public FastReader() {
            br = new BufferedReader(new
                    InputStreamReader(System.in));
        } FastReader {
            br = new BufferedReader(new
                    InputStreamReader(System.in));
        } br = new BufferedReader(new
                    InputStreamReader(System.in)) br new BufferedReader(new
                    InputStreamReader(System.in)) String next() {
            while (st == null || !st.hasMoreElements())
            {
                try
                {
                    st = new StringTokenizer(br.readLine());
                }
                catch (IOException e)
                {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        } next {
            while (st == null || !st.hasMoreElements())
            {
                try
                {
                    st = new StringTokenizer(br.readLine());
                }
                catch (IOException e)
                {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        } while (st == null || !st.hasMoreElements())
            {
                try
                {
                    st = new StringTokenizer(br.readLine());
                }
                catch (IOException e)
                {
                    e.printStackTrace();
                }
            } st == null || !st.hasMoreElements() st == null st null !st.hasMoreElements() st.hasMoreElements() st.hasMoreElements st {
                try
                {
                    st = new StringTokenizer(br.readLine());
                }
                catch (IOException e)
                {
                    e.printStackTrace();
                }
            } try
                {
                    st = new StringTokenizer(br.readLine());
                }
                catch (IOException e)
                {
                    e.printStackTrace();
                } catch (IOException e)
                {
                    e.printStackTrace();
                } IOException e {
                    e.printStackTrace();
                } e.printStackTrace() e.printStackTrace e {
                    st = new StringTokenizer(br.readLine());
                } st = new StringTokenizer(br.readLine()) st new StringTokenizer(br.readLine()) return st.nextToken(); st.nextToken() st.nextToken st int nextInt()
        {
            return Integer.parseInt(next());
        } nextInt {
            return Integer.parseInt(next());
        } return Integer.parseInt(next()); Integer.parseInt(next()) Integer.parseInt Integer next() next long nextLong()
        {
            return Long.parseLong(next());
        } nextLong {
            return Long.parseLong(next());
        } return Long.parseLong(next()); Long.parseLong(next()) Long.parseLong Long next() next double nextDouble()
        {
            return Double.parseDouble(next());
        } nextDouble {
            return Double.parseDouble(next());
        } return Double.parseDouble(next()); Double.parseDouble(next()) Double.parseDouble Double next() next String nextLine() {
            String str = "";
            try
            {
                str = br.readLine();
            }
            catch (IOException e)
            {
                e.printStackTrace();
            }
            return str;
        } nextLine {
            String str = "";
            try
            {
                str = br.readLine();
            }
            catch (IOException e)
            {
                e.printStackTrace();
            }
            return str;
        } String str = ""; str "" try
            {
                str = br.readLine();
            }
            catch (IOException e)
            {
                e.printStackTrace();
            } catch (IOException e)
            {
                e.printStackTrace();
            } IOException e {
                e.printStackTrace();
            } e.printStackTrace() e.printStackTrace e {
                str = br.readLine();
            } str = br.readLine() str br.readLine() br.readLine br return str; str public class Main {
    int[][] css;

    public static void main(String args[]) {
        new Main().run();
    }

    void run() {
        FastReader sc = new FastReader();
        css = new int[3][3];
        for (int i = 0; i < 3; i++) {
            for (int j = 0; j < 3; j++) {
                css[i][j] = sc.nextInt();
            }
        }
        solve();
    }

    void solve() {
        boolean flag = true;
        if (!(css[0][0] - css[0][1] == css[1][0] - css[1][1] &&
                css[1][0] - css[1][1] == css[2][0] - css[2][1])) {
            flag = false;
        } else if (!(css[0][1] - css[0][2] == css[1][1] - css[1][2] &&
                css[1][1] - css[1][2] == css[2][1] - css[2][2])) {
            flag = false;
        }
        if (flag) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }
    }

    static class FastReader {
        BufferedReader br;
        StringTokenizer st;

        public FastReader() {
            br = new BufferedReader(new
                    InputStreamReader(System.in));
        }

        String next() {
            while (st == null || !st.hasMoreElements())
            {
                try
                {
                    st = new StringTokenizer(br.readLine());
                }
                catch (IOException e)
                {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }

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

        long nextLong()
        {
            return Long.parseLong(next());
        }

        double nextDouble()
        {
            return Double.parseDouble(next());
        }

        String nextLine() {
            String str = "";
            try
            {
                str = br.readLine();
            }
            catch (IOException e)
            {
                e.printStackTrace();
            }
            return str;
        }
    }
} public class Main {
    int[][] css;

    public static void main(String args[]) {
        new Main().run();
    }

    void run() {
        FastReader sc = new FastReader();
        css = new int[3][3];
        for (int i = 0; i < 3; i++) {
            for (int j = 0; j < 3; j++) {
                css[i][j] = sc.nextInt();
            }
        }
        solve();
    }

    void solve() {
        boolean flag = true;
        if (!(css[0][0] - css[0][1] == css[1][0] - css[1][1] &&
                css[1][0] - css[1][1] == css[2][0] - css[2][1])) {
            flag = false;
        } else if (!(css[0][1] - css[0][2] == css[1][1] - css[1][2] &&
                css[1][1] - css[1][2] == css[2][1] - css[2][2])) {
            flag = false;
        }
        if (flag) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }
    }

    static class FastReader {
        BufferedReader br;
        StringTokenizer st;

        public FastReader() {
            br = new BufferedReader(new
                    InputStreamReader(System.in));
        }

        String next() {
            while (st == null || !st.hasMoreElements())
            {
                try
                {
                    st = new StringTokenizer(br.readLine());
                }
                catch (IOException e)
                {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }

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

        long nextLong()
        {
            return Long.parseLong(next());
        }

        double nextDouble()
        {
            return Double.parseDouble(next());
        }

        String nextLine() {
            String str = "";
            try
            {
                str = br.readLine();
            }
            catch (IOException e)
            {
                e.printStackTrace();
            }
            return str;
        }
    }
} Main

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.StringTokenizer;

public class Main {
    int[][] css;

    public static void main(String args[]) {
        new Main().run();
    }

    void run() {
        FastReader sc = new FastReader();
        css = new int[3][3];
        for (int i = 0; i < 3; i++) {
            for (int j = 0; j < 3; j++) {
                css[i][j] = sc.nextInt();
            }
        }
        solve();
    }

    void solve() {
        boolean flag = true;
        if (!(css[0][0] - css[0][1] == css[1][0] - css[1][1] &&
                css[1][0] - css[1][1] == css[2][0] - css[2][1])) {
            flag = false;
        } else if (!(css[0][1] - css[0][2] == css[1][1] - css[1][2] &&
                css[1][1] - css[1][2] == css[2][1] - css[2][2])) {
            flag = false;
        }
        if (flag) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }
    }

    static class FastReader {
        BufferedReader br;
        StringTokenizer st;

        public FastReader() {
            br = new BufferedReader(new
                    InputStreamReader(System.in));
        }

        String next() {
            while (st == null || !st.hasMoreElements())
            {
                try
                {
                    st = new StringTokenizer(br.readLine());
                }
                catch (IOException e)
                {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }

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

        long nextLong()
        {
            return Long.parseLong(next());
        }

        double nextDouble()
        {
            return Double.parseDouble(next());
        }

        String nextLine() {
            String str = "";
            try
            {
                str = br.readLine();
            }
            catch (IOException e)
            {
                e.printStackTrace();
            }
            return str;
        }
    }
}
