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

#ifdef _RUTHEN
#include <debug.hpp>
#else
#define show(...) true
#endif

using ll = long long;
#define rep(i, n) for (int i = 0; i < (n); i++)
template <class T> using V = vector<T>;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    V<string> A(6);
    rep(i, 6) cin >> A[i];
    sort(A.begin(), A.end());
    A.erase(unique(A.begin(), A.end()), A.end());
    V<int> B(6);
    rep(i, 6) B[i] = lower_bound(A.begin(), A.end(), A[i]) - A.begin();
    auto f = [](int a, int b) -> bool { return (a & b) ^ 1; };
    rep(b, 1 << 6) {
        if (f(f(f(b >> B[0] & 1, b >> B[1] & 1), b >> B[2] & 1), f(f(b >> B[3] & 1, b >> B[4] & 1), b >> B[5] & 1))) {
            cout << "YES\n";
            return 0;
        }
    }
    cout << "NO\n";
    return 0;
}