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

int main() {
	set<int>a;
	unordered_set<int>b;
	a.insert(4);
	a.insert(5);
	b.insert(4);
	b.insert(5);
	if(a.find(4)!=a.end()){
		cout<<"YES";
	}else{
		cout<<"NO";
	}
	map<int,int>m;
	unordered_map<int,int>m1;
	m[1]=1;m[2]=2;
	m1[1]=1;m1[2]=2;
	if(m.find(4)!=m.end()){
		cout<<"YES";
	}else{
		cout<<"NO";
	}
	cout<<m1[2]<<endl;
	return 0;
}