#define _USE_MATH_DEFINES
#include <bits/stdc++.h>
using namespace std;
#define FOR(i,m,n) for(int i=(m);i<(n);++i)
#define REP(i,n) FOR(i,0,n)
#define ALL(v) (v).begin(),(v).end()
using ll = long long;
constexpr int INF = 0x3f3f3f3f;
constexpr long long LINF = 0x3f3f3f3f3f3f3f3fLL;
constexpr double EPS = 1e-8;
constexpr int MOD = 998244353;
// constexpr int MOD = 1000000007;
constexpr int DY4[]{1, 0, -1, 0}, DX4[]{0, -1, 0, 1};
constexpr int DY8[]{1, 1, 0, -1, -1, -1, 0, 1};
constexpr int DX8[]{0, -1, -1, -1, 0, 1, 1, 1};
template <typename T, typename U>
inline bool chmax(T& a, U b) { return a < b ? (a = b, true) : false; }
template <typename T, typename U>
inline bool chmin(T& a, U b) { return a > b ? (a = b, true) : false; }
struct IOSetup {
  IOSetup() {
    std::cin.tie(nullptr);
    std::ios_base::sync_with_stdio(false);
    std::cout << fixed << setprecision(20);
  }
} iosetup;

bool nand(const bool a, const bool b) {
  return !(a && b);
}

bool satify(const bool a, const bool b, const bool c,
            const bool d, const bool e, const bool f) {
  return nand(nand(nand(a, b), c), nand(nand(d, e), f));
}

int main() {
  constexpr int N = 6;
  string a[N]; REP(i, N) cin >> a[i];
  vector<string> b(N);
  copy(a, a + N, b.begin());
  sort(ALL(b));
  b.erase(unique(ALL(b)), b.end());
  const int l = b.size();
  int index[N];
  REP(i, N) index[i] = lower_bound(ALL(b), a[i]) - b.begin();
  REP(bit, 1 << l) {
    vector<bool> t_or_f(l);
    REP(i, l) t_or_f[i] = bit >> i & 1;
    if (satify(t_or_f[index[0]], t_or_f[index[1]], t_or_f[index[2]],
               t_or_f[index[3]], t_or_f[index[4]], t_or_f[index[5]])) {
      cout << "YES\n";
      return 0;
    }
  }
  cout << "NO\n";
  return 0;
}