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

public class Main {

    static int[][] C;

    public static void main(String[] args) {
        FastScanner sc = new FastScanner(System.in);

        C = new int[3][3];
        for (int i = 0; i < 3; i++) {
            for (int j = 0; j < 3; j++) {
                C[i][j] = sc.nextInt();
            }
        }

        System.out.println(solve() ? "Yes" : "No");
    }

    static boolean solve() {
        for (int a0 = 0; a0 <= 100; a0++) {
            if( isOk(a0) ) {
                return true;
            }
        }
        return false;
    }

    static boolean isOk(int a0) {
        int[] b = new int[3];
        for (int i = 0; i < 3; i++) {
            b[i] = C[0][i] - a0;
        }
        int[] a = new int[3];
        a[0] = a0;
        a[1] = C[1][0] - b[0];
        a[2] = C[2][0] - b[0];

        for (int i = 0; i < 3; i++) {
            for (int j = 0; j < 3; j++) {
                if( a[i] + b[j] != C[i][j] ) return false;
            }
        }
        return true;
    }

    @SuppressWarnings("unused")
    static class FastScanner {
        private BufferedReader reader;
        private StringTokenizer tokenizer;

        FastScanner(InputStream in) {
            reader = new BufferedReader(new InputStreamReader(in));
            tokenizer = null;
        }

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

        String nextLine() {
            if (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    return reader.readLine();
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken("\n");
        }

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

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

        int[] nextIntArray(int n) {
            int[] a = new int[n];
            for (int i = 0; i < n; i++)
                a[i] = nextInt();
            return a;
        }

        long[] nextLongArray(int n) {
            long[] a = new long[n];
            for (int i = 0; i < n; i++)
                a[i] = nextLong();
            return a;
        }
    }
}

/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz