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

#define M_PI 3.14159265358979323846
using ull = unsigned long long;
using ll = long long;
#define endl "\n"

#define REP(i, n) for (ll i = 0; i < n; i++)
#define REPR(i, n) for (ll i = n; i >= 0; i--)
#define FOR(i, m, n) for (ll i = m; i < n; i++)
#define even(x) (x) % 2 == 0
#define odd(x) (x) % 2 != 0
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define pcnt __builtin_popcount
#define buli(x) __builtin_popcountll(x)
#define UNIQUE(v) v.erase(unique(v.begin(), v.end()), v.end());
#define IN1(type, x) type x; cin >> x;
#define inll(x) ll x; cin >> x;
#define INIT() cin.tie(0); ios::sync_with_stdio(0); cout << fixed << setprecision(20)

// these functions return the position of result of Binary Search.
#define LB(s, t, x) (int) (lower_bound(s, t, x) - s)
#define UB(s, t, x) (int) (upper_bound(s, t, x) - s)

namespace {
    const ll MOD_CONST = (ll)(1e9 + 7);
    const ll CFM = (ll)(998244353);
    ll qp(ll a, ll b, int mo) { ll ans = 1; do { if (b & 1) ans = 1ll * ans * a % mo; a = 1ll * a * a % mo; } while (b >>= 1); return ans; }
    ll gcd(ll a, ll b) { return b ? gcd(b, a % b) : a; }
    ll lcm(ll a, ll b) { ll temp = gcd(a, b); return temp ? (a / temp * b) : 0; }
    int mDays[] = { 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
    int dx[4] = {1, 0, -1, 0}, dy[4] = {0, 1, 0, -1};
    int dx8[] = { 1, -1, 0, 0, 1, 1, -1, -1 }, dy8[] = { 0, 0, -1, 1, -1, 1, -1, 1 };

    template<typename F>
    class
    #if defined(__has_cpp_attribute) && __has_cpp_attribute(nodiscard)
    [[nodiscard]]
    #elif defined(__GNUC__) && __GNUC_PREREQ(3, 4)
    __attribute__((warn_unused_result))
    #endif  // defined(__has_cpp_attribute) && __has_cpp_attribute(nodiscard)
    FixPoint : F
    {
    public:
    explicit constexpr FixPoint(F&& f) noexcept
        : F(std::forward<F>(f))
    {}

    template<typename... Args>
    constexpr decltype(auto)
    operator()(Args&&... args) const
    {
        return F::operator()(*this, std::forward<Args>(args)...);
    }
    };  // class FixPoint
    template<typename F>
    static inline constexpr decltype(auto)
    makeFixPoint(F&& f) noexcept {
    return FixPoint<F>{std::forward<F>(f)};
    }

    template <typename T>
    vector<T> make_v(size_t a) { return vector<T>(a); }
    template <typename T, typename... Ts>
    auto make_v(size_t a, size_t b, Ts... ts) { return vector<decltype(make_v<T>(b, ts...))>(a, make_v<T>(b, ts...)); }
    template <typename T, typename V>
    typename enable_if<is_class<T>::value == 0>::type
    fill_v(T &t, const V &v) { t = v; }
    template <typename T, typename V>
    typename enable_if<is_class<T>::value != 0>::type
    fill_v(T &t, const V &v) { for (auto &e : t) fill_v(e, v); }

    template <typename T>
    vector<T> pows(int b, int n) { // vec{b^0, b^1, b^2, ...}
        vector<T> ret;
        T x = 1;
        while (ret.size() < n) {
            ret.push_back(x);
            x *= b;
        }
        return ret;
    }
    template <class T>
    bool chmax(T &a, const T &b) { if (a < b) { a = b; return 1; } return 0; }
    template <class T>
    bool chmin(T &a, const T &b) { if (b < a) { a = b; return 1; } return 0; }

    inline tuple<ll, ll> rotate45(tuple<ll, ll> point) { ll x = get<0>(point), y = get<1>(point); return tuple<ll, ll>(x + y, x - y); }
    inline bool rangeCheck2D(int nx, int ny, int Width, int Height) { return nx >= 0 and nx < Width and ny >= 0 and ny < Height; }

    template <typename T>
    vector<T> INPA(ll n) {
        vector<T> x;
        REP(i, n) {
            T tmp; cin >> tmp;
            x.push_back(tmp);
        }
        return move(x);
    }
    // base^x % MOD  - O(x)
    ll p_base(ll base, ll x) {
        ll ans = 1;
        REP(i, x) {
            ans *= base;
            ans %= MOD_CONST;
        }
        return ans;
    }
    template <typename T>
    void out(T o) { cout << o << endl; }
    template <typename T>
    void out(vector<T> &out) { REP(i, (int)out.size()) { cout << out[i]; if (i == (int)out.size() - 1) cout << endl; else cout << " "; } }
    template <typename T>
    void out(vector<vector<T>> o) { REP(i, o.size()) out(o[i]); }
    string i_query(ll x, ll y) {
        cout << "? " << x << " " << y << endl;
        fflush(stdout);
        string ret; cin >> ret;
        return ret;
    }
    void i_answer(ll ans) {
        cout << "! " << ans << endl;
        fflush(stdout);
    }
}

// lambda expression
// auto f = [](int arg1, double arg2) { return ret; };
// lambda recursion
// auto result = makeFixPoint([&](auto rec, int pos, int v) -> int {
//	   rec(pos, v);
// })(0, 1);
// auto func = makeFixPoint([]() -> int {});
// int ret = func();

// tuple binding
// auto t = make_tuple(0, 0);
// int x, y; tie(x, y) = t;
// auto [x, y] = t;

// for pair
// auto [a, b] = pair<int, int>({v1, v2});

// bitset<N> bs(ini_val); // N must be constant
// bs.reset(); // reset all

int main(void)
{
    INIT(); // comment out for Interective Program

    vector<int> a(3), b(3);
    REP(i, 3) cin >> a[i] >> b[i];
    vector<char> used(3);
    vector<char> visited(5);
    int c = 1;
    while (true) {
        visited[c] = true;
        bool all = true;
        FOR(i,1, 5) {
            if (not visited[i])
                all = false;
        }
        if (all) break;
        bool f = false;
        REP(i, 3) {
            if (used[i]) continue;
            if (a[i] == c) {
                if (visited[b[i]]) continue;
                c = b[i];
                f = true;
                break;
            }
            if (b[i] == c) {
                if (visited[a[i]]) continue;
                c = a[i];
                f = true;
                break;
            }
        }
        if (not f) {
            out("NO");
            return 0;
        }
    }
    out("YES");

    return 0;
}
//*/

Measured memory_bytes: 256