#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using P = pair<ll,ll>;
#define fix(x) fixed << setprecision(x)
#define asc(x) x, vector<x>, greater<x>
#define rep(i, n) for(ll i = 0; i < n; i++)
#define all(x) (x).begin(),(x).end()
template<class T>bool chmin(T&a, const T&b){if(a>b){a=b;return 1;}return 0;}
template<class T>bool chmax(T&a, const T&b){if(a<b){a=b;return 1;}return 0;}
bool f(vector<bool> v){
    return !(!(!v[0]+!v[1])+!v[2])+!(!(!v[3]+!v[4])+!v[5]);
}
int main(){
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    vector<int> a(6);
    int now = 0;
    string s;
    map<string, int> mp;
    rep(i,6){
        cin >> s;
        if(mp.count(s)) a[i] = mp[s];
        else a[i] = now, mp[s] = now++;
    }
    bool ans = false;
    rep(i,1<<now){
        vector<bool> v(6);
        rep(j,6){
            v[j] = (i & (1 << a[j]));
        }
        ans = ans + f(v);
    }
    cout << (ans?"YES\n":"NO\n");
    return 0;
}