//------------------------------------------
// C++ templete 
//------------------------------------------
#include <bits/stdc++.h>
using namespace std;
using ll = long long;

#define endl "\n"

//typedef
//------------------------------------------
typedef pair<int, int> PII;
typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<string> VS;
typedef vector<PII> VP;

//REPEAT
//------------------------------------------
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n)  FOR(i,0,n)

//container util
//------------------------------------------
#define pb push_back
#define paired make_pair
#define ALL(a) (a).begin(),(a).end()
#define PRINT(V) for (auto v : (V)) cout << v << " "
#define SORT(V) sort((V).begin(),(V).end())
#define RSORT(V) sort((V).rbegin(), (V).rend())

//constant
//------------------------------------------
const int MOD = 1000000007;
const int INF = 1061109567;
const double EPS = 1e-10;
const double PI  = acos(-1.0);
int dx[4]={1,0,-1,0};
int dy[4]={0,1,0,-1};

//math
//------------------------------------------
int QP(int a,int b){int ans=1;do{if(b&1)ans=1ll*ans*a%MOD;a=1ll*a*a%MOD;}while(b>>=1);return ans;}
int QP(int a,int b,int MOD){int ans=1;do{if(b&1)ans=1ll*ans*a%MOD;a=1ll*a*a%MOD;}while(b>>=1);return ans;}
int GCD(int a,int b){return b?GCD(b,a%b):a;}

//debug
//------------------------------------------
#define dump(x)  cerr << #x << " = " << (x) << endl;
#define debug(x) cerr << #x << " = " << (x) << " (L" << __LINE__ << ")" << " " << __FILE__ << endl;

//grobal variable
//------------------------------------------
int N,M;
VI Vec;

//動的計画法で役に立つ関数
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }

//最大公約数と最小公倍数
ll gcd(ll a, ll b) {
    if(b==0)return a;
    return gcd(b, a%b);
}

ll lcm(ll a, ll b) {
  ll g = gcd(a, b);
  return a/g*b;
}

vector<vector<long long> > comb(int n) {
  vector<vector<long long> > v(n + 1,vector<long long>(n + 1, 0));
  for (int i = 0; i < v.size(); i++) {
    v[i][0] = 1;
    v[i][i] = 1;
  }
  for (int j = 1; j < v.size(); j++) {
    for (int k = 1; k < j; k++) {
      v[j][k] = (v[j - 1][k - 1] + v[j - 1][k]);
    }
  }
  return v;
}

bool check(VI A, VI B)
{
    VI C;
    REP(i, 3)
    {
        C.pb(A[i] - B[i]);
    }
    SORT(C);
    return C.front()==C.back();
}

int main() 
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    
    bool is_ok=true;
    VVI C(3, VI(3));
    REP(i,3)
    {
        REP(j,3)
        {
            cin >> C.at(i).at(j);
        }
    }
    REP(i, 3)
    {
        REP(j,3)
        {
            if (i > j)
            {
                VI A, B;
                A.pb(C.at(0).at(i));
                A.pb(C.at(1).at(i));
                A.pb(C.at(2).at(i));
                B.pb(C.at(0).at(j));
                B.pb(C.at(1).at(j));
                B.pb(C.at(2).at(j));
                if (!(check(C.at(i), C.at(j)) && check(A, B)))
                {
                    is_ok=false;
                    break;
                }
            }
        }
    }
    
    cout << (is_ok ? "Yes" : "No") << endl;
  
    return 0;
}



Measured memory_bytes: 256