#include <bits/stdc++.h>
#define REP(i, n) for (int i = 0; i < (int)(n); i++)
#define REPR(i, n) for(int i = (int)(n); i >= 0; i--)
#define FOR(i, s, n) for (int i = (s); i < (int)(n); i++)
#define ALL(v) v.begin(), v.end()
using namespace std;
typedef long long ll;

ll N, K, T, W, H, M, C;

const int MAX = 5100000;
const ll MOD = 1e9 + 7;

const double PI=3.14159265358979323846;


long long fac[MAX], finv[MAX], inv[MAX];

vector<double> cx, cy, c;
 ll MM = 1e12;

void COMinit() {
    fac[0] = fac[1] = 1;
    finv[0] = finv[1] = 1;
    inv[1] = 1;
    for (int i = 2; i < MAX; i++){
        fac[i] = fac[i - 1] * i % MOD;
        inv[i] = MOD - inv[MOD%i] * (MOD / i) % MOD;
        finv[i] = finv[i - 1] * inv[i] % MOD;
    }
}

long long COM(int n, int k){
    if (n < k) return 0;
    if (n < 0 || k < 0) return 0;
    return fac[n] * (finv[k] * finv[n - k] % MOD) % MOD;
}

ll modinv(ll a) {
    ll b = MOD, u = 1, v = 0;
    while (b) {
        ll t = a / b;
        a -= t * b; swap(a, b);
        u -= t * v; swap(u, v);
    }
    u %= MOD;
    if (u < 0) u += MOD;
    return u;
}

ll modpow(ll x, ll n) {
  ll ret = 1;
  while(n > 0) {
    if(n & 1) (ret *= x) %= MOD;
    (x *= x) %= MOD;
    n >>= 1;
  }
  return ret;
}

struct Eratos {
    vector<int> primes;
    vector<bool> isprime;
    vector<int> min_factor;

    Eratos(int MAX) : primes(),
                      isprime(MAX+1, true),
                      min_factor(MAX+1, -1) {
        isprime[0] = isprime[1] = false;
        min_factor[0] = 0, min_factor[1] = 1;
        for (int i = 2; i <= MAX; ++i) {
            if (!isprime[i]) continue;
            primes.push_back(i);
            min_factor[i] = i;
            for (int j = i*2; j <= MAX; j += i) {
                isprime[j] = false;
                if (min_factor[j] == -1) min_factor[j] = i;
            }
        }
    }

    // prime factorization
    vector<pair<int,int>> prime_factorize(int n) {
        vector<pair<int,int> > res;
        while (n != 1) {
            int prime = min_factor[n];
            int exp = 0;
            while (min_factor[n] == prime) {
                ++exp;
                n /= prime;
            }
            res.push_back(make_pair(prime, exp));
        }
        return res;
    }
};

ll gcd(ll a, ll b) {
  if(a < b) return gcd(b, a);
  ll r;
  while ((r=a%b)) {
    a = b;
    b = r;
  }
  return b;
}

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

  

struct UnionFind {
    vector<int> par; 

    UnionFind(int N) : par(N) { 
        for(int i = 0; i < N; i++) par[i] = i;
    }

    int root(int x) { 
        if (par[x] == x) return x;
        return par[x] = root(par[x]);
    }

    void unite(int x, int y) {
        int rx = root(x);
        int ry = root(y); 
        if (rx == ry) return; 
        par[rx] = ry; 
    }

    bool same(int x, int y) { 
        int rx = root(x);
        int ry = root(y);
        return rx == ry;
    }
};

int main(){
    std::vector<int> cnt(4);
    REP(i,3){
        int a,b;
        cin >> a >> b;
        ++cnt[a-1]; ++cnt[b-1];
    }
    if(cnt[0] > 2 or cnt[1] > 2 or cnt[2] > 2 or cnt[3] > 2) cout << "NO";
    else cout << "YES";
    
}


Measured memory_bytes: 256