/// Containers Start
#include <iostream>
#include <string>
#include <set>
#include <map>
#include <stack>
#include <queue>
#include <vector>
#include <utility>
#include <iomanip>
#include <sstream>
#include <bitset>
#include <cstdlib>
#include <iterator>
#include <algorithm>
/// C Header Files
#include <cstdio>
#include <cctype>
#include <cmath>
#include <math.h>
#include <ctime>
#include <cstring>
/// Containers End


using namespace std;


/// Math Start
#define PI                    acos(-1.0)
#define Pi                    3.141592653589793
#define EPS (1e-7)
#define INF (1e9)
/// Math End


/// Extra Start
#define nn                    '\n'
#define pb                    push_back
#define SS                    stringstream
#define ull                   unsigned long long
#define mod                   1000000007
#define SIZE                  2000001
#define _cin                  ios_base::sync_with_stdio(0);  cin.tie(0);
#define sz(a)                 int((a).size())
#define space                 " "
#define all(x)                (x).begin(), (x).end()
#define Ignore                cin.ignore()
#define StringToInt           if ( ! (istringstream(s) >> n) ) n = 0;
/// Extra End


/// Functions Start
template<class T>
T Multiply(T a, T b) { return a * b; }

template<class T>
T larger(T a, T b) { return (a > b ? a : b); }

template<class T>
T smaller(T a, T b) { return (a < b ? a : b); }

template<class T>
T gcd(T a, T b) {
    if (b == 0)return a;
    return gcd(b, a % b);
}

template<class T>
T lcm(T a, T b) { return a / gcd(a, b) * b; }

template<class T>
string converter(T n) {
    SS x;
    x << n;
    return x.str();
}

#define rep(i, n) for(int i = 0;i < n;i++)
#define FOR(i, a, b) for(int i=(a);i<=(b);i++)
#define FORD(i, a, b) for(int i=(a);i>=(b);i--)
#define FORA(arr) for(auto &i:arr)
#define Cin(a)            cin>>a;
#define Cin2(a, b)        cin>>a>>b;
#define Cin3(a, b, c)        cin>>a>>b>>c;
#define Cin4(a, b, c, d)   cin>>a>>b>>c>>d;
/// Functions End


/// Array Start
#define SET(a)                memset( a, -1,    sizeof a )
#define CLR(a)                memset( a,  0,    sizeof a )
#define MEM(a, val)            memset( a,  val,  sizeof(a) )
/// Array End


/// Debug Start
#define deb(x) cout << #x << ": " << x << endl
#define deb2(x, y) cout << #x << ": " << x << '\t' << #y << ": " << y << endl
#define deb3(x, y, z) cout << #x << ": " << x << '\t' << #y << ": " << y << '\t' << #z << ": " << z << end
/// Debug End


/// TypeDef Start
typedef long long int ll;
typedef map<string, int> msi;
typedef map<int, int> mii;
typedef map<ll, ll> mll;
typedef map<char, int> mci;
typedef map<int, string> mis;
typedef pair<int, int> pii;
typedef pair<string, int> psi;
typedef pair<string, string> pss;
typedef vector<int> vi;
typedef vector<string> vs;
typedef vector<char> vc;
typedef vector<bool> vb;
typedef vector<pii> vii;
/// TypeDef End

/****************** Geometry *****************/

template<typename T>
inline T PointDistanceHorVer(T x1, T y1, T x2, T y2) { return abs(x1 - x2) + abs(y1 - y2); }

template<typename T>
inline T PointDistanceDiagonally(T x1, T y1, T x2, T y2) { return sqrt((x2 - x1) * (x2 - x1) + (y2 - y1) * (y2 - y1)); }

template<typename T>
inline T PointDistanceMinimum(T x1, T y1, T x2, T y2) {
    T tmp1 = abs(x1 - x2);
    T tmp2 = abs(y1 - y2);
    T tmp3 = abs(tmp1 - tmp2);
    T tmp4 = min(tmp1, tmp2);
    return tmp3 + tmp4;
}

template<typename T>
inline T PointDistance3D(T x1, T y1, T z1, T x2, T y2, T z2) {
    return sqrt(square(x2 - x1) + square(y2 - y1) + square(z2 - z1));
}

template<typename T>
inline T Cube(T a) { return a * a * a; }

template<typename T>
inline T RectengularPrism(T a, T b, T c) { return a * b * c; }

template<typename T>
inline T Pyramid(T base, T height) { return (1 / 3) * base * height; }

template<typename T>
inline T Ellipsoid(T r1, T r2, T r3) { return (4 / 3) * PI * r1 * r2 * r3; }

template<typename T>
inline T IrregualarPrism(T base, T height) { return base * height; }

template<typename T>
inline T Sphere(T radius) { return (4 / 3) * PI * radius * radius * radius; }

template<typename T>
inline T CylinderB(T base, T height) { return base * height; } // base and height
template<typename T>
inline T CylinderR(T radius, T height) { return PI * radius * radius * height; } // radius and height
template<typename T>
inline T Cone(T radius, T base, T height) { return (1 / 3) * PI * radius * radius * height; }

/**>>>>>>>>>>>>>>>>>>> END <<<<<<<<<<<<<<<<<<**/


int main(void) {
    int n;
    string s;

    int c[3][3],cc[3][3];
    int a[3][3], b[3][3];

    rep(i, 3) {
        rep(j, 3) {
            Cin(c[i][j]);
            cc[i][j] = c[i][j];
        }
    }


    for (int i = -100; i <= 100; i++) {
        for (int j = -100; j <= 100; j++) {
            for (int k = -100; k <= 100; k++) {
                rep(p, 3) {
                    rep(q, 3) {
                        if (p == 0) a[p][q] = i;
                        if (p == 1) a[p][q] = j;
                        if (p == 2) a[p][q] = k;
                    }
                }

//                if (a[0][0] == a[0][1] && a[0][1] == a[0][2] && a[0][0] == 0) {
//                    if (a[1][0] == a[1][1] && a[1][1] == a[1][2] && a[1][0] == 1) {
//                        if (a[2][0] == a[2][1] && a[2][1] == a[2][2] && a[2][0] == 1) {
//
//                            {
//                                rep(i, 3) {
//                                    cout << c[i][0] << " " << c[i][1] << " " << c[i][2] << endl;
//                                }
//
//                                rep(i, 3) {
//                                    rep(j, 3) {
//                                        c[i][j] = c[i][j] - a[i][j];
//                                    }
//                                }
//                            }
//
//                        }
//                    }
//                }





                rep(i, 3) {
                    rep(j, 3) {
                        c[i][j] = cc[i][j] - a[i][j];
                    }
                }

                int flag = 1;
                rep(j, 3) {
                    if (c[0][j] == c[1][j] && c[1][j] == c[2][j]) flag *= 1;
                    else flag *= 0;
                }

                if (flag) {
                    cout << "Yes" << endl;
                    return 0;
                }

            }
        }
    }


    cout << "No" << endl;


    return 0;
}






Measured memory_bytes: 256