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

using ll = long long;
using ull = unsigned long long;
using ld = long double;
template<class t> using vc = vector<t>;
template<class t> using vvc = vc<vc<t>>;
using pi = pair<int,int>;
using pl = pair<ll,ll>;
using vi = vc<int>;
using vvi = vvc<int>;
using vl = vc<ll>;
using vvl = vvc<ll>;

#define rep(i,a,b) for (int i = (int)(a); i < (int)(b); i++)
#define irep(i,a,b) for (int i = (int)(a); i > (int)(b); i--)
#define all(a) a.begin(),a.end()
#define print(n) cout << n << '\n'
#define pritn(n) print(n)
#define printv(n,a) {copy(all(n),ostream_iterator<a>(cout," ")); cout<<"\n";}
#define printvv(n,a) {for(auto itr:n) printv(itr,a);}
#define rup(a,b) (a+b-1)/b
#define input(A,N) rep(i,0,N) cin>>A[i]
#define chmax(a,b) a = max(a,b)
#define chmin(a,b) a = min(a,b)


int main(){
    cout << fixed << setprecision(15);
    
    vc<string> a(6);
    input(a,6);
    vc<string>b = a;
    sort(all(b));
    b.erase(unique(all(b)),b.end());
    vi now(6);
    rep(i,0,6){
        int ni = lower_bound(all(b),a[i]) - b.begin();
        now[i] = ni;
    }
    bool p = false;

    for(int s = 0;s<(1<<now.size());s++){
        vi nn(6);
        rep(i,0,6){
            if(s>>now[i]&1) nn[i] = 1;
            else nn[i] = 0;
        }
        nn[1] = !(nn[0]&nn[1]);
        nn[2] = !(nn[2]&nn[1]);
        nn[4] = !(nn[3]&nn[4]);
        nn[5] = !(nn[5]&nn[4]);
        nn[2] = !(nn[2]&nn[5]);
        if(nn[2]) p = true;
        if(p) break;
    }
    if(p) print("YES");
    else print("NO");

    //system("pause");
    return 0;
}