#include <bits/stdc++.h>
#define rep(i,n) for(int i = 0; i < (n); i++)
using namespace std;
typedef long long ll;

int main(){
    cin.tie(0);
    ios::sync_with_stdio(0);
    
    vector<string> A(6);
    rep(i,6) cin >> A[i];
    auto B = A;
    sort(B.begin(), B.end());
    B.erase(unique(B.begin(), B.end()), B.end());

    int N = int(B.size());
    auto NAND = [](int P, int Q) {
        return !(P == 1 && Q == 1);
    };
    rep(S,1<<N) {
        vector<int> P(6, 0);
        rep(i,6) {
            int n = -1;
            rep(j,N) if(B[j] == A[i]) n = j;
            if(S & (1 << n)) P[i] = 1;
        }

        if(NAND(NAND(NAND(P[0], P[1]), P[2]), NAND(NAND(P[3], P[4]), P[5]))) {
            cout << "YES" << endl;
            return 0;
        }
    }

    cout << "NO" << endl;
    return 0;
}