//なんか嘘っぽいの
#include <iostream>
#include <cassert>
#include <map>

using namespace std;

int main(){
	int n = 7;
	map<int,int> m;
	for(int i=0; i<n; i++){
		int a;
		cin >> a;
		m[a]++;
	}

	bool ok = true;
	for(auto p : m){
		if(p == *m.begin()){
			if(p.second != 1) ok = false;
		}
		if(p == *m.rbegin()){
			if(p.second != 1) ok = false;
		}
		if(p.second > 2) ok = false;
	}

	if(ok) cout << "YES" << endl;
	else cout << "NO" << endl;

	return 0;
}