#pragma region header
#include <bits/stdc++.h>
using namespace std;

#define CPP_CAT(x,y) CPP_CAT_I(x,y)
#define CPP_CAT_I(x,y) x ## y
//#define CPP_STR(x) CPP_STR_I(x)
//#define CPP_STR_I(args...) #args
//#define ASSERT(expr...) assert((expr))

using i8 = int8_t;
using u8 = uint8_t;
using i16 = int16_t;
using u16 = uint16_t;
using i32 = int32_t;
using u32 = uint32_t;
using i64 = int64_t;
using u64 = uint64_t;
using f32 = float;
using f64 = double;
//using f80 = __float80;

constexpr i64 INF = 1'010'000'000'000'000'017LL;
constexpr i64 MOD = 1'000'000'007LL;
constexpr f64 EPS = 1e-12;
constexpr f64 PI = 3.14159265358979323846;
constexpr char EL[] = "\n";

#define FOR(i, start, end) for(i64 i = (start), CPP_CAT(i,xxxx_end)=(end); i < CPP_CAT(i,xxxx_end); ++i)
#define REP(i, n) FOR(i, 0, n)
#define ALL(f,c,...) (([&](decltype((c)) cccc) { return (f)(std::begin(cccc), std::end(cccc), ## __VA_ARGS__); })(c))
#define UNIQUE(v) v.erase(unique(v.begin(), v.end()), v.end());

template<typename T = i64>
T IN() { T x; cin >> x; return (x); }

template<typename C>
i64 SIZE(const C& c) { return static_cast<i64>(c.size()); }
template<typename T, size_t N>
i64 SIZE(const T(&)[N]) { return static_cast<i64>(N); }

template<typename T, typename U, typename Comp = less<>>
bool chmax(T& xmax, const U& x, Comp comp = {}) {
	if (comp(xmax, x)) {
		xmax = x;
		return true;
	}
	return false;
}
template<typename T, typename U, typename Comp = less<>>
bool chmin(T& xmin, const U& x, Comp comp = {}) {
	if (comp(x, xmin)) {
		xmin = x;
		return true;
	}
	return false;
}

void print() {
	cout << EL;
}
template <class Head, class... Tail>
void print(Head&& head, Tail&&... tail) {
	cout << head;
	if (sizeof...(tail) != 0) cout << " ";
	print(forward<Tail>(tail)...);
}
template <class T>
void print(vector<T> &vec) {
	for (auto& a : vec) {
		cout << a;
		if (&a != &vec.back()) cout << " ";
	}
	cout << EL;
}
template <class T>
void print(vector<vector<T>> &df) {
	for (auto& vec : df) {
		print(vec);
	}
}

struct ProconInit {
	static constexpr int IOS_PREC = 15;
	static constexpr bool AUTOFLUSH = false;

	ProconInit() {
		cin.tie(nullptr);
		ios::sync_with_stdio(false);
		cout << fixed << setprecision(IOS_PREC);
		if (AUTOFLUSH)
			cout << unitbuf;
	}
} PROCON_INIT;
#pragma endregion

signed solve()
{
	int c[3][3];
	REP(i, 3) REP(j, 3) cin >> c[i][j];

	int a, b, di, dj;
	a = 0; b = 1;
	di = dj = 1000;
	REP(i, 3)
	{
		if (di == 1000) di = c[i][a] - c[i][b];
		else if (c[i][a] - c[i][b] != di) { print("No"); return 0; }
		if (dj == 1000) dj = c[a][i] - c[b][i];
		else if (c[a][i] - c[b][i] != dj) { print("No"); return 0; }
	}
	a = 1; b = 2;
	di = dj = 1000;
	REP(i, 3)
	{
		if (di == 1000) di = c[i][a] - c[i][b];
		else if (c[i][a] - c[i][b] != di) { print("No"); return 0; }
		if (dj == 1000) dj = c[a][i] - c[b][i];
		else if (c[a][i] - c[b][i] != dj) { print("No"); return 0; }
	}
	a = 0; b = 2;
	di = dj = 1000;
	REP(i, 3)
	{
		if (di == 1000) di = c[i][a] - c[i][b];
		else if (c[i][a] - c[i][b] != di) { print("No"); return 0; }
		if (dj == 1000) dj = c[a][i] - c[b][i];
		else if (c[a][i] - c[b][i] != dj) { print("No"); return 0; }
	}
	print("Yes");
	return 0;
}

#ifndef LOCALCODE
signed main()
{
	return solve();
}
#endif


Measured memory_bytes: 256