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

//nand
bool nand(bool a, bool b) {
	if (!(a && b)) return true;
	else return false;
}

int main(){
	
	map<string, vector<int>> MAP;
	vector<string> Alist;  //添字一覧（ダブりなし）
	
	for (int i = 0; i < 6; i++) {
		string A_n;
		cin >> A_n;
		
		if(MAP[A_n].empty()) Alist.push_back(A_n);
		
		MAP[A_n].push_back(i);
	}
	
	int m = Alist.size(); //添字の種類数
	
	//bit全探索
	for (int i = 0; i < (1<<m); i++) {
		
		vector<bool> P_n(6, false);
		
		for (int j = 0; j < m; j++) {
			if (i & (1<<j)) {
				for (int n : MAP[Alist.at(j)]) P_n[n] = true;
			}
		}
		
		if (nand(nand(nand(P_n[0], P_n[1]), P_n[2]), nand(nand(P_n[3], P_n[4]), P_n[5]))) {
			cout << "YES" << endl;
			return 0;
		}
	}
	
	cout << "NO" << endl;
}