import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.io.BufferedWriter;
import java.io.Writer;
import java.io.OutputStreamWriter;
import java.util.InputMismatchException;
import java.io.IOException;
import java.io.InputStream;

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

  static class CTakahashisInformation {
    public void solve(int testNumber, InputReader in, OutputWriter out) {
      int[][] grid = in.readIntTable(3, 3);

      for (int x = 0; x <= 200; ++x) {

        int[] a = new int[3];
        int[] b = new int[3];
        a[0] = x;
        for (int i = 0; i < 3; ++i) b[i] = grid[0][i] - x;
        a[1] = grid[1][1] - b[1];
        a[2] = grid[2][2] - b[2];

        boolean ok = true;

        for (int i = 0; i < 3; ++i)
          for (int j = 0; j < 3; ++j) if (a[i] + b[j] != grid[i][j]) ok = false;

        if (ok) {
          out.printLine("Yes");
          return;
        }
      }
      out.printLine("No");
    }
  }

  static class InputReader {
    private InputStream stream;
    private byte[] buf = new byte[1024];
    private int curChar;
    private int numChars;
    private InputReader.SpaceCharFilter filter;

    public InputReader(InputStream stream) {
      this.stream = stream;
    }

    public int[][] readIntTable(int rowCount, int columnCount) {
      int[][] table = new int[rowCount][];
      for (int i = 0; i < rowCount; i++) {
        table[i] = readIntArray(columnCount);
      }
      return table;
    }

    public int[] readIntArray(int size) {
      int[] array = new int[size];
      for (int i = 0; i < size; i++) {
        array[i] = readInt();
      }
      return array;
    }

    public int read() {
      if (numChars == -1) {
        throw new InputMismatchException();
      }
      if (curChar >= numChars) {
        curChar = 0;
        try {
          numChars = stream.read(buf);
        } catch (IOException e) {
          throw new InputMismatchException();
        }
        if (numChars <= 0) {
          return -1;
        }
      }
      return buf[curChar++];
    }

    public int readInt() {
      int c = read();
      while (isSpaceChar(c)) {
        c = read();
      }
      int sgn = 1;
      if (c == '-') {
        sgn = -1;
        c = read();
      }
      int res = 0;
      do {
        if (c < '0' || c > '9') {
          throw new InputMismatchException();
        }
        res *= 10;
        res += c - '0';
        c = read();
      } while (!isSpaceChar(c));
      return res * sgn;
    }

    public boolean isSpaceChar(int c) {
      if (filter != null) {
        return filter.isSpaceChar(c);
      }
      return isWhitespace(c);
    }

    public static boolean isWhitespace(int c) {
      return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
    }

    public interface SpaceCharFilter {
      public boolean isSpaceChar(int ch);
    }
  }

  static class OutputWriter {
    private final PrintWriter writer;

    public OutputWriter(OutputStream outputStream) {
      writer = new PrintWriter(new BufferedWriter(new OutputStreamWriter(outputStream)));
    }

    public OutputWriter(Writer writer) {
      this.writer = new PrintWriter(writer);
    }

    public void print(Object... objects) {
      for (int i = 0; i < objects.length; i++) {
        if (i != 0) {
          writer.print(' ');
        }
        writer.print(objects[i]);
      }
    }

    public void printLine(Object... objects) {
      print(objects);
      writer.println();
    }

    public void close() {
      writer.close();
    }
  }
} import java.io.OutputStream; OutputStream java.io import java.io.IOException; IOException java.io import java.io.InputStream; InputStream java.io import java.io.OutputStream; OutputStream java.io import java.io.PrintWriter; PrintWriter java.io import java.io.BufferedWriter; BufferedWriter java.io import java.io.Writer; Writer java.io import java.io.OutputStreamWriter; OutputStreamWriter java.io import java.util.InputMismatchException; InputMismatchException java.util import java.io.IOException; IOException 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);
    OutputWriter out = new OutputWriter(outputStream);
    CTakahashisInformation solver = new CTakahashisInformation();
    solver.solve(1, in, out);
    out.close();
  }

  static class CTakahashisInformation {
    public void solve(int testNumber, InputReader in, OutputWriter out) {
      int[][] grid = in.readIntTable(3, 3);

      for (int x = 0; x <= 200; ++x) {

        int[] a = new int[3];
        int[] b = new int[3];
        a[0] = x;
        for (int i = 0; i < 3; ++i) b[i] = grid[0][i] - x;
        a[1] = grid[1][1] - b[1];
        a[2] = grid[2][2] - b[2];

        boolean ok = true;

        for (int i = 0; i < 3; ++i)
          for (int j = 0; j < 3; ++j) if (a[i] + b[j] != grid[i][j]) ok = false;

        if (ok) {
          out.printLine("Yes");
          return;
        }
      }
      out.printLine("No");
    }
  }

  static class InputReader {
    private InputStream stream;
    private byte[] buf = new byte[1024];
    private int curChar;
    private int numChars;
    private InputReader.SpaceCharFilter filter;

    public InputReader(InputStream stream) {
      this.stream = stream;
    }

    public int[][] readIntTable(int rowCount, int columnCount) {
      int[][] table = new int[rowCount][];
      for (int i = 0; i < rowCount; i++) {
        table[i] = readIntArray(columnCount);
      }
      return table;
    }

    public int[] readIntArray(int size) {
      int[] array = new int[size];
      for (int i = 0; i < size; i++) {
        array[i] = readInt();
      }
      return array;
    }

    public int read() {
      if (numChars == -1) {
        throw new InputMismatchException();
      }
      if (curChar >= numChars) {
        curChar = 0;
        try {
          numChars = stream.read(buf);
        } catch (IOException e) {
          throw new InputMismatchException();
        }
        if (numChars <= 0) {
          return -1;
        }
      }
      return buf[curChar++];
    }

    public int readInt() {
      int c = read();
      while (isSpaceChar(c)) {
        c = read();
      }
      int sgn = 1;
      if (c == '-') {
        sgn = -1;
        c = read();
      }
      int res = 0;
      do {
        if (c < '0' || c > '9') {
          throw new InputMismatchException();
        }
        res *= 10;
        res += c - '0';
        c = read();
      } while (!isSpaceChar(c));
      return res * sgn;
    }

    public boolean isSpaceChar(int c) {
      if (filter != null) {
        return filter.isSpaceChar(c);
      }
      return isWhitespace(c);
    }

    public static boolean isWhitespace(int c) {
      return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
    }

    public interface SpaceCharFilter {
      public boolean isSpaceChar(int ch);
    }
  }

  static class OutputWriter {
    private final PrintWriter writer;

    public OutputWriter(OutputStream outputStream) {
      writer = new PrintWriter(new BufferedWriter(new OutputStreamWriter(outputStream)));
    }

    public OutputWriter(Writer writer) {
      this.writer = new PrintWriter(writer);
    }

    public void print(Object... objects) {
      for (int i = 0; i < objects.length; i++) {
        if (i != 0) {
          writer.print(' ');
        }
        writer.print(objects[i]);
      }
    }

    public void printLine(Object... objects) {
      print(objects);
      writer.println();
    }

    public void close() {
      writer.close();
    }
  }
} Main public static void main(String[] args) {
    InputStream inputStream = System.in;
    OutputStream outputStream = System.out;
    InputReader in = new InputReader(inputStream);
    OutputWriter out = new OutputWriter(outputStream);
    CTakahashisInformation solver = new CTakahashisInformation();
    solver.solve(1, in, out);
    out.close();
  } main {
    InputStream inputStream = System.in;
    OutputStream outputStream = System.out;
    InputReader in = new InputReader(inputStream);
    OutputWriter out = new OutputWriter(outputStream);
    CTakahashisInformation solver = new CTakahashisInformation();
    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) OutputWriter out = new OutputWriter(outputStream); out new OutputWriter(outputStream) CTakahashisInformation solver = new CTakahashisInformation(); solver new CTakahashisInformation() solver.solve(1, in, out) solver.solve solver 1 in out out.close() out.close out String[] args args static class CTakahashisInformation {
    public void solve(int testNumber, InputReader in, OutputWriter out) {
      int[][] grid = in.readIntTable(3, 3);

      for (int x = 0; x <= 200; ++x) {

        int[] a = new int[3];
        int[] b = new int[3];
        a[0] = x;
        for (int i = 0; i < 3; ++i) b[i] = grid[0][i] - x;
        a[1] = grid[1][1] - b[1];
        a[2] = grid[2][2] - b[2];

        boolean ok = true;

        for (int i = 0; i < 3; ++i)
          for (int j = 0; j < 3; ++j) if (a[i] + b[j] != grid[i][j]) ok = false;

        if (ok) {
          out.printLine("Yes");
          return;
        }
      }
      out.printLine("No");
    }
  } CTakahashisInformation public void solve(int testNumber, InputReader in, OutputWriter out) {
      int[][] grid = in.readIntTable(3, 3);

      for (int x = 0; x <= 200; ++x) {

        int[] a = new int[3];
        int[] b = new int[3];
        a[0] = x;
        for (int i = 0; i < 3; ++i) b[i] = grid[0][i] - x;
        a[1] = grid[1][1] - b[1];
        a[2] = grid[2][2] - b[2];

        boolean ok = true;

        for (int i = 0; i < 3; ++i)
          for (int j = 0; j < 3; ++j) if (a[i] + b[j] != grid[i][j]) ok = false;

        if (ok) {
          out.printLine("Yes");
          return;
        }
      }
      out.printLine("No");
    } solve {
      int[][] grid = in.readIntTable(3, 3);

      for (int x = 0; x <= 200; ++x) {

        int[] a = new int[3];
        int[] b = new int[3];
        a[0] = x;
        for (int i = 0; i < 3; ++i) b[i] = grid[0][i] - x;
        a[1] = grid[1][1] - b[1];
        a[2] = grid[2][2] - b[2];

        boolean ok = true;

        for (int i = 0; i < 3; ++i)
          for (int j = 0; j < 3; ++j) if (a[i] + b[j] != grid[i][j]) ok = false;

        if (ok) {
          out.printLine("Yes");
          return;
        }
      }
      out.printLine("No");
    } int[][] grid = in.readIntTable(3, 3); grid in.readIntTable(3, 3) in.readIntTable in 3 3 for (int x = 0; x <= 200; ++x) {

        int[] a = new int[3];
        int[] b = new int[3];
        a[0] = x;
        for (int i = 0; i < 3; ++i) b[i] = grid[0][i] - x;
        a[1] = grid[1][1] - b[1];
        a[2] = grid[2][2] - b[2];

        boolean ok = true;

        for (int i = 0; i < 3; ++i)
          for (int j = 0; j < 3; ++j) if (a[i] + b[j] != grid[i][j]) ok = false;

        if (ok) {
          out.printLine("Yes");
          return;
        }
      } int x = 0; int x = 0; x 0 x <= 200 x 200 ++x ++x x {

        int[] a = new int[3];
        int[] b = new int[3];
        a[0] = x;
        for (int i = 0; i < 3; ++i) b[i] = grid[0][i] - x;
        a[1] = grid[1][1] - b[1];
        a[2] = grid[2][2] - b[2];

        boolean ok = true;

        for (int i = 0; i < 3; ++i)
          for (int j = 0; j < 3; ++j) if (a[i] + b[j] != grid[i][j]) ok = false;

        if (ok) {
          out.printLine("Yes");
          return;
        }
      } {

        int[] a = new int[3];
        int[] b = new int[3];
        a[0] = x;
        for (int i = 0; i < 3; ++i) b[i] = grid[0][i] - x;
        a[1] = grid[1][1] - b[1];
        a[2] = grid[2][2] - b[2];

        boolean ok = true;

        for (int i = 0; i < 3; ++i)
          for (int j = 0; j < 3; ++j) if (a[i] + b[j] != grid[i][j]) ok = false;

        if (ok) {
          out.printLine("Yes");
          return;
        }
      } int[] a = new int[3]; a new int[3] 3 int[] b = new int[3]; b new int[3] 3 a[0] = x a[0] a 0 x for (int i = 0; i < 3; ++i) b[i] = grid[0][i] - x; int i = 0; int i = 0; i 0 i < 3 i 3 ++i ++i i b[i] = grid[0][i] - x; b[i] = grid[0][i] - x b[i] b i grid[0][i] - x grid[0][i] grid[0] grid 0 i x a[1] = grid[1][1] - b[1] a[1] a 1 grid[1][1] - b[1] grid[1][1] grid[1] grid 1 1 b[1] b 1 a[2] = grid[2][2] - b[2] a[2] a 2 grid[2][2] - b[2] grid[2][2] grid[2] grid 2 2 b[2] b 2 boolean ok = true; ok true for (int i = 0; i < 3; ++i)
          for (int j = 0; j < 3; ++j) if (a[i] + b[j] != grid[i][j]) ok = false; int i = 0; int i = 0; i 0 i < 3 i 3 ++i ++i i for (int j = 0; j < 3; ++j) if (a[i] + b[j] != grid[i][j]) ok = false; for (int j = 0; j < 3; ++j) if (a[i] + b[j] != grid[i][j]) ok = false; int j = 0; int j = 0; j 0 j < 3 j 3 ++j ++j j if (a[i] + b[j] != grid[i][j]) ok = false; if (a[i] + b[j] != grid[i][j]) ok = false; a[i] + b[j] != grid[i][j] a[i] + b[j] a[i] a i b[j] b j grid[i][j] grid[i] grid i j ok = false ok false if (ok) {
          out.printLine("Yes");
          return;
        } ok {
          out.printLine("Yes");
          return;
        } out.printLine("Yes") out.printLine out "Yes" return; out.printLine("No") out.printLine out "No" int testNumber testNumber InputReader in in OutputWriter out out static class InputReader {
    private InputStream stream;
    private byte[] buf = new byte[1024];
    private int curChar;
    private int numChars;
    private InputReader.SpaceCharFilter filter;

    public InputReader(InputStream stream) {
      this.stream = stream;
    }

    public int[][] readIntTable(int rowCount, int columnCount) {
      int[][] table = new int[rowCount][];
      for (int i = 0; i < rowCount; i++) {
        table[i] = readIntArray(columnCount);
      }
      return table;
    }

    public int[] readIntArray(int size) {
      int[] array = new int[size];
      for (int i = 0; i < size; i++) {
        array[i] = readInt();
      }
      return array;
    }

    public int read() {
      if (numChars == -1) {
        throw new InputMismatchException();
      }
      if (curChar >= numChars) {
        curChar = 0;
        try {
          numChars = stream.read(buf);
        } catch (IOException e) {
          throw new InputMismatchException();
        }
        if (numChars <= 0) {
          return -1;
        }
      }
      return buf[curChar++];
    }

    public int readInt() {
      int c = read();
      while (isSpaceChar(c)) {
        c = read();
      }
      int sgn = 1;
      if (c == '-') {
        sgn = -1;
        c = read();
      }
      int res = 0;
      do {
        if (c < '0' || c > '9') {
          throw new InputMismatchException();
        }
        res *= 10;
        res += c - '0';
        c = read();
      } while (!isSpaceChar(c));
      return res * sgn;
    }

    public boolean isSpaceChar(int c) {
      if (filter != null) {
        return filter.isSpaceChar(c);
      }
      return isWhitespace(c);
    }

    public static boolean isWhitespace(int c) {
      return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
    }

    public interface SpaceCharFilter {
      public boolean isSpaceChar(int ch);
    }
  } InputReader private InputStream stream; stream private byte[] buf = new byte[1024]; buf new byte[1024] 1024 private int curChar; curChar private int numChars; numChars private InputReader.SpaceCharFilter filter; filter public InputReader(InputStream stream) {
      this.stream = stream;
    } InputReader {
      this.stream = stream;
    } this.stream = stream this.stream this this.stream stream InputStream stream stream public int[][] readIntTable(int rowCount, int columnCount) {
      int[][] table = new int[rowCount][];
      for (int i = 0; i < rowCount; i++) {
        table[i] = readIntArray(columnCount);
      }
      return table;
    } readIntTable {
      int[][] table = new int[rowCount][];
      for (int i = 0; i < rowCount; i++) {
        table[i] = readIntArray(columnCount);
      }
      return table;
    } int[][] table = new int[rowCount][]; table new int[rowCount][] rowCount for (int i = 0; i < rowCount; i++) {
        table[i] = readIntArray(columnCount);
      } int i = 0; int i = 0; i 0 i < rowCount i rowCount i++ i++ i {
        table[i] = readIntArray(columnCount);
      } {
        table[i] = readIntArray(columnCount);
      } table[i] = readIntArray(columnCount) table[i] table i readIntArray(columnCount) readIntArray columnCount return table; table int rowCount rowCount int columnCount columnCount public int[] readIntArray(int size) {
      int[] array = new int[size];
      for (int i = 0; i < size; i++) {
        array[i] = readInt();
      }
      return array;
    } readIntArray {
      int[] array = new int[size];
      for (int i = 0; i < size; i++) {
        array[i] = readInt();
      }
      return array;
    } int[] array = new int[size]; array new int[size] size for (int i = 0; i < size; i++) {
        array[i] = readInt();
      } int i = 0; int i = 0; i 0 i < size i size i++ i++ i {
        array[i] = readInt();
      } {
        array[i] = readInt();
      } array[i] = readInt() array[i] array i readInt() readInt return array; array int size size public int read() {
      if (numChars == -1) {
        throw new InputMismatchException();
      }
      if (curChar >= numChars) {
        curChar = 0;
        try {
          numChars = stream.read(buf);
        } catch (IOException e) {
          throw new InputMismatchException();
        }
        if (numChars <= 0) {
          return -1;
        }
      }
      return buf[curChar++];
    } read {
      if (numChars == -1) {
        throw new InputMismatchException();
      }
      if (curChar >= numChars) {
        curChar = 0;
        try {
          numChars = stream.read(buf);
        } catch (IOException e) {
          throw new InputMismatchException();
        }
        if (numChars <= 0) {
          return -1;
        }
      }
      return buf[curChar++];
    } if (numChars == -1) {
        throw new InputMismatchException();
      } numChars == -1 numChars -1 1 {
        throw new InputMismatchException();
      } throw new InputMismatchException(); new InputMismatchException() if (curChar >= numChars) {
        curChar = 0;
        try {
          numChars = stream.read(buf);
        } catch (IOException e) {
          throw new InputMismatchException();
        }
        if (numChars <= 0) {
          return -1;
        }
      } curChar >= numChars curChar numChars {
        curChar = 0;
        try {
          numChars = stream.read(buf);
        } catch (IOException e) {
          throw new InputMismatchException();
        }
        if (numChars <= 0) {
          return -1;
        }
      } curChar = 0 curChar 0 try {
          numChars = stream.read(buf);
        } catch (IOException e) {
          throw new InputMismatchException();
        } catch (IOException e) {
          throw new InputMismatchException();
        } IOException e {
          throw new InputMismatchException();
        } throw new InputMismatchException(); new InputMismatchException() {
          numChars = stream.read(buf);
        } numChars = stream.read(buf) numChars stream.read(buf) stream.read stream buf if (numChars <= 0) {
          return -1;
        } numChars <= 0 numChars 0 {
          return -1;
        } return -1; -1 1 return buf[curChar++]; buf[curChar++] buf curChar++ curChar public int readInt() {
      int c = read();
      while (isSpaceChar(c)) {
        c = read();
      }
      int sgn = 1;
      if (c == '-') {
        sgn = -1;
        c = read();
      }
      int res = 0;
      do {
        if (c < '0' || c > '9') {
          throw new InputMismatchException();
        }
        res *= 10;
        res += c - '0';
        c = read();
      } while (!isSpaceChar(c));
      return res * sgn;
    } readInt {
      int c = read();
      while (isSpaceChar(c)) {
        c = read();
      }
      int sgn = 1;
      if (c == '-') {
        sgn = -1;
        c = read();
      }
      int res = 0;
      do {
        if (c < '0' || c > '9') {
          throw new InputMismatchException();
        }
        res *= 10;
        res += c - '0';
        c = read();
      } while (!isSpaceChar(c));
      return res * sgn;
    } int c = read(); c read() read while (isSpaceChar(c)) {
        c = read();
      } isSpaceChar(c) isSpaceChar c {
        c = read();
      } c = read() c read() read int sgn = 1; sgn 1 if (c == '-') {
        sgn = -1;
        c = read();
      } c == '-' c '-' {
        sgn = -1;
        c = read();
      } sgn = -1 sgn -1 1 c = read() c read() read int res = 0; res 0 do {
        if (c < '0' || c > '9') {
          throw new InputMismatchException();
        }
        res *= 10;
        res += c - '0';
        c = read();
      } while (!isSpaceChar(c)); !isSpaceChar(c) isSpaceChar(c) isSpaceChar c {
        if (c < '0' || c > '9') {
          throw new InputMismatchException();
        }
        res *= 10;
        res += c - '0';
        c = read();
      } if (c < '0' || c > '9') {
          throw new InputMismatchException();
        } c < '0' || c > '9' c < '0' c '0' c > '9' c '9' {
          throw new InputMismatchException();
        } throw new InputMismatchException(); new InputMismatchException() res *= 10 res 10 res += c - '0' res c - '0' c '0' c = read() c read() read return res * sgn; res * sgn res sgn public boolean isSpaceChar(int c) {
      if (filter != null) {
        return filter.isSpaceChar(c);
      }
      return isWhitespace(c);
    } isSpaceChar {
      if (filter != null) {
        return filter.isSpaceChar(c);
      }
      return isWhitespace(c);
    } if (filter != null) {
        return filter.isSpaceChar(c);
      } filter != null filter null {
        return filter.isSpaceChar(c);
      } return filter.isSpaceChar(c); filter.isSpaceChar(c) filter.isSpaceChar filter c return isWhitespace(c); isWhitespace(c) isWhitespace c int c c public static boolean isWhitespace(int c) {
      return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
    } isWhitespace {
      return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
    } return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1; c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1 c == '\t' c == '\r' c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1 c == ' ' c ' ' c == '\n' c '\n' c == '\r' c '\r' c == '\t' c '\t' c == -1 c -1 1 int c c public interface SpaceCharFilter {
      public boolean isSpaceChar(int ch);
    } SpaceCharFilter public boolean isSpaceChar(int ch); isSpaceChar int ch ch static class OutputWriter {
    private final PrintWriter writer;

    public OutputWriter(OutputStream outputStream) {
      writer = new PrintWriter(new BufferedWriter(new OutputStreamWriter(outputStream)));
    }

    public OutputWriter(Writer writer) {
      this.writer = new PrintWriter(writer);
    }

    public void print(Object... objects) {
      for (int i = 0; i < objects.length; i++) {
        if (i != 0) {
          writer.print(' ');
        }
        writer.print(objects[i]);
      }
    }

    public void printLine(Object... objects) {
      print(objects);
      writer.println();
    }

    public void close() {
      writer.close();
    }
  } OutputWriter private final PrintWriter writer; writer public OutputWriter(OutputStream outputStream) {
      writer = new PrintWriter(new BufferedWriter(new OutputStreamWriter(outputStream)));
    } OutputWriter {
      writer = new PrintWriter(new BufferedWriter(new OutputStreamWriter(outputStream)));
    } writer = new PrintWriter(new BufferedWriter(new OutputStreamWriter(outputStream))) writer new PrintWriter(new BufferedWriter(new OutputStreamWriter(outputStream))) OutputStream outputStream outputStream public OutputWriter(Writer writer) {
      this.writer = new PrintWriter(writer);
    } OutputWriter {
      this.writer = new PrintWriter(writer);
    } this.writer = new PrintWriter(writer) this.writer this this.writer new PrintWriter(writer) Writer writer writer public void print(Object... objects) {
      for (int i = 0; i < objects.length; i++) {
        if (i != 0) {
          writer.print(' ');
        }
        writer.print(objects[i]);
      }
    } print {
      for (int i = 0; i < objects.length; i++) {
        if (i != 0) {
          writer.print(' ');
        }
        writer.print(objects[i]);
      }
    } for (int i = 0; i < objects.length; i++) {
        if (i != 0) {
          writer.print(' ');
        }
        writer.print(objects[i]);
      } int i = 0; int i = 0; i 0 i < objects.length i objects.length objects objects.length i++ i++ i {
        if (i != 0) {
          writer.print(' ');
        }
        writer.print(objects[i]);
      } {
        if (i != 0) {
          writer.print(' ');
        }
        writer.print(objects[i]);
      } if (i != 0) {
          writer.print(' ');
        } i != 0 i 0 {
          writer.print(' ');
        } writer.print(' ') writer.print writer ' ' writer.print(objects[i]) writer.print writer objects[i] objects i Object... objects objects public void printLine(Object... objects) {
      print(objects);
      writer.println();
    } printLine {
      print(objects);
      writer.println();
    } print(objects) print objects writer.println() writer.println writer Object... objects objects public void close() {
      writer.close();
    } close {
      writer.close();
    } writer.close() writer.close writer public class Main {
  public static void main(String[] args) {
    InputStream inputStream = System.in;
    OutputStream outputStream = System.out;
    InputReader in = new InputReader(inputStream);
    OutputWriter out = new OutputWriter(outputStream);
    CTakahashisInformation solver = new CTakahashisInformation();
    solver.solve(1, in, out);
    out.close();
  }

  static class CTakahashisInformation {
    public void solve(int testNumber, InputReader in, OutputWriter out) {
      int[][] grid = in.readIntTable(3, 3);

      for (int x = 0; x <= 200; ++x) {

        int[] a = new int[3];
        int[] b = new int[3];
        a[0] = x;
        for (int i = 0; i < 3; ++i) b[i] = grid[0][i] - x;
        a[1] = grid[1][1] - b[1];
        a[2] = grid[2][2] - b[2];

        boolean ok = true;

        for (int i = 0; i < 3; ++i)
          for (int j = 0; j < 3; ++j) if (a[i] + b[j] != grid[i][j]) ok = false;

        if (ok) {
          out.printLine("Yes");
          return;
        }
      }
      out.printLine("No");
    }
  }

  static class InputReader {
    private InputStream stream;
    private byte[] buf = new byte[1024];
    private int curChar;
    private int numChars;
    private InputReader.SpaceCharFilter filter;

    public InputReader(InputStream stream) {
      this.stream = stream;
    }

    public int[][] readIntTable(int rowCount, int columnCount) {
      int[][] table = new int[rowCount][];
      for (int i = 0; i < rowCount; i++) {
        table[i] = readIntArray(columnCount);
      }
      return table;
    }

    public int[] readIntArray(int size) {
      int[] array = new int[size];
      for (int i = 0; i < size; i++) {
        array[i] = readInt();
      }
      return array;
    }

    public int read() {
      if (numChars == -1) {
        throw new InputMismatchException();
      }
      if (curChar >= numChars) {
        curChar = 0;
        try {
          numChars = stream.read(buf);
        } catch (IOException e) {
          throw new InputMismatchException();
        }
        if (numChars <= 0) {
          return -1;
        }
      }
      return buf[curChar++];
    }

    public int readInt() {
      int c = read();
      while (isSpaceChar(c)) {
        c = read();
      }
      int sgn = 1;
      if (c == '-') {
        sgn = -1;
        c = read();
      }
      int res = 0;
      do {
        if (c < '0' || c > '9') {
          throw new InputMismatchException();
        }
        res *= 10;
        res += c - '0';
        c = read();
      } while (!isSpaceChar(c));
      return res * sgn;
    }

    public boolean isSpaceChar(int c) {
      if (filter != null) {
        return filter.isSpaceChar(c);
      }
      return isWhitespace(c);
    }

    public static boolean isWhitespace(int c) {
      return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
    }

    public interface SpaceCharFilter {
      public boolean isSpaceChar(int ch);
    }
  }

  static class OutputWriter {
    private final PrintWriter writer;

    public OutputWriter(OutputStream outputStream) {
      writer = new PrintWriter(new BufferedWriter(new OutputStreamWriter(outputStream)));
    }

    public OutputWriter(Writer writer) {
      this.writer = new PrintWriter(writer);
    }

    public void print(Object... objects) {
      for (int i = 0; i < objects.length; i++) {
        if (i != 0) {
          writer.print(' ');
        }
        writer.print(objects[i]);
      }
    }

    public void printLine(Object... objects) {
      print(objects);
      writer.println();
    }

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

  static class CTakahashisInformation {
    public void solve(int testNumber, InputReader in, OutputWriter out) {
      int[][] grid = in.readIntTable(3, 3);

      for (int x = 0; x <= 200; ++x) {

        int[] a = new int[3];
        int[] b = new int[3];
        a[0] = x;
        for (int i = 0; i < 3; ++i) b[i] = grid[0][i] - x;
        a[1] = grid[1][1] - b[1];
        a[2] = grid[2][2] - b[2];

        boolean ok = true;

        for (int i = 0; i < 3; ++i)
          for (int j = 0; j < 3; ++j) if (a[i] + b[j] != grid[i][j]) ok = false;

        if (ok) {
          out.printLine("Yes");
          return;
        }
      }
      out.printLine("No");
    }
  }

  static class InputReader {
    private InputStream stream;
    private byte[] buf = new byte[1024];
    private int curChar;
    private int numChars;
    private InputReader.SpaceCharFilter filter;

    public InputReader(InputStream stream) {
      this.stream = stream;
    }

    public int[][] readIntTable(int rowCount, int columnCount) {
      int[][] table = new int[rowCount][];
      for (int i = 0; i < rowCount; i++) {
        table[i] = readIntArray(columnCount);
      }
      return table;
    }

    public int[] readIntArray(int size) {
      int[] array = new int[size];
      for (int i = 0; i < size; i++) {
        array[i] = readInt();
      }
      return array;
    }

    public int read() {
      if (numChars == -1) {
        throw new InputMismatchException();
      }
      if (curChar >= numChars) {
        curChar = 0;
        try {
          numChars = stream.read(buf);
        } catch (IOException e) {
          throw new InputMismatchException();
        }
        if (numChars <= 0) {
          return -1;
        }
      }
      return buf[curChar++];
    }

    public int readInt() {
      int c = read();
      while (isSpaceChar(c)) {
        c = read();
      }
      int sgn = 1;
      if (c == '-') {
        sgn = -1;
        c = read();
      }
      int res = 0;
      do {
        if (c < '0' || c > '9') {
          throw new InputMismatchException();
        }
        res *= 10;
        res += c - '0';
        c = read();
      } while (!isSpaceChar(c));
      return res * sgn;
    }

    public boolean isSpaceChar(int c) {
      if (filter != null) {
        return filter.isSpaceChar(c);
      }
      return isWhitespace(c);
    }

    public static boolean isWhitespace(int c) {
      return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
    }

    public interface SpaceCharFilter {
      public boolean isSpaceChar(int ch);
    }
  }

  static class OutputWriter {
    private final PrintWriter writer;

    public OutputWriter(OutputStream outputStream) {
      writer = new PrintWriter(new BufferedWriter(new OutputStreamWriter(outputStream)));
    }

    public OutputWriter(Writer writer) {
      this.writer = new PrintWriter(writer);
    }

    public void print(Object... objects) {
      for (int i = 0; i < objects.length; i++) {
        if (i != 0) {
          writer.print(' ');
        }
        writer.print(objects[i]);
      }
    }

    public void printLine(Object... objects) {
      print(objects);
      writer.println();
    }

    public void close() {
      writer.close();
    }
  }
} Main
import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.io.BufferedWriter;
import java.io.Writer;
import java.io.OutputStreamWriter;
import java.util.InputMismatchException;
import java.io.IOException;
import java.io.InputStream;

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

  static class CTakahashisInformation {
    public void solve(int testNumber, InputReader in, OutputWriter out) {
      int[][] grid = in.readIntTable(3, 3);

      for (int x = 0; x <= 200; ++x) {

        int[] a = new int[3];
        int[] b = new int[3];
        a[0] = x;
        for (int i = 0; i < 3; ++i) b[i] = grid[0][i] - x;
        a[1] = grid[1][1] - b[1];
        a[2] = grid[2][2] - b[2];

        boolean ok = true;

        for (int i = 0; i < 3; ++i)
          for (int j = 0; j < 3; ++j) if (a[i] + b[j] != grid[i][j]) ok = false;

        if (ok) {
          out.printLine("Yes");
          return;
        }
      }
      out.printLine("No");
    }
  }

  static class InputReader {
    private InputStream stream;
    private byte[] buf = new byte[1024];
    private int curChar;
    private int numChars;
    private InputReader.SpaceCharFilter filter;

    public InputReader(InputStream stream) {
      this.stream = stream;
    }

    public int[][] readIntTable(int rowCount, int columnCount) {
      int[][] table = new int[rowCount][];
      for (int i = 0; i < rowCount; i++) {
        table[i] = readIntArray(columnCount);
      }
      return table;
    }

    public int[] readIntArray(int size) {
      int[] array = new int[size];
      for (int i = 0; i < size; i++) {
        array[i] = readInt();
      }
      return array;
    }

    public int read() {
      if (numChars == -1) {
        throw new InputMismatchException();
      }
      if (curChar >= numChars) {
        curChar = 0;
        try {
          numChars = stream.read(buf);
        } catch (IOException e) {
          throw new InputMismatchException();
        }
        if (numChars <= 0) {
          return -1;
        }
      }
      return buf[curChar++];
    }

    public int readInt() {
      int c = read();
      while (isSpaceChar(c)) {
        c = read();
      }
      int sgn = 1;
      if (c == '-') {
        sgn = -1;
        c = read();
      }
      int res = 0;
      do {
        if (c < '0' || c > '9') {
          throw new InputMismatchException();
        }
        res *= 10;
        res += c - '0';
        c = read();
      } while (!isSpaceChar(c));
      return res * sgn;
    }

    public boolean isSpaceChar(int c) {
      if (filter != null) {
        return filter.isSpaceChar(c);
      }
      return isWhitespace(c);
    }

    public static boolean isWhitespace(int c) {
      return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
    }

    public interface SpaceCharFilter {
      public boolean isSpaceChar(int ch);
    }
  }

  static class OutputWriter {
    private final PrintWriter writer;

    public OutputWriter(OutputStream outputStream) {
      writer = new PrintWriter(new BufferedWriter(new OutputStreamWriter(outputStream)));
    }

    public OutputWriter(Writer writer) {
      this.writer = new PrintWriter(writer);
    }

    public void print(Object... objects) {
      for (int i = 0; i < objects.length; i++) {
        if (i != 0) {
          writer.print(' ');
        }
        writer.print(objects[i]);
      }
    }

    public void printLine(Object... objects) {
      print(objects);
      writer.println();
    }

    public void close() {
      writer.close();
    }
  }
}
