#pragma GCC optimize("Ofast")
#include <iostream>
#include <vector>
#include <algorithm>
#include <map>
#include <queue>
#include <cstdio>
#include <ctime>
#include <assert.h>
#include <chrono>
#include <random>
#include <numeric>
#include <set>
#include <deque>
#include <stack>
#include <sstream>
#include <utility>
#include <cstring>
#include <unordered_map>
#include <unordered_set>
#include <tuple>
#include <array>
#include <bitset>
using namespace std;
typedef long long int ll;
typedef unsigned long long ull;

mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
ll myRand(ll B) {
    return (ull)rng() % B;
}
inline double time() {
    return static_cast<long double>(chrono::duration_cast<chrono::nanoseconds>(chrono::steady_clock::now().time_since_epoch()).count()) * 1e-9;
}

bool nand(int a,int b){
    if(a and b) return false;
    else return true;
}

int main(){
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    vector<int> v(6);
    map<string,int> mp;
    for(int i=0;i<6;i++){
        string s; cin >> s;
        if(mp.find(s) == mp.end()){
            int sz = mp.size();
            mp[s] = sz;
        }
        v[i] = mp[s];
    }
    int m = mp.size();
    for(int i=0;i<(1<<m);i++){
        auto bit=[&](int j)->int{
            return (1<<j)&i;
        };
        bool f1 = nand(bit(v[0]),bit(v[1]));
        bool f2 = nand(f1, bit(v[2]));
        bool f3 = nand(bit(v[3]), bit(v[4]));
        bool f4 = nand(f3, bit(v[5]));
        bool f5 = nand(f2, f4);
        if(f5){
            cout << "YES" << endl;
            return 0;
        }
    }
    cout << "NO" << endl;
}