#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
template <class type1>
#define ll long long int
#define endl "\n"
#define ordered_set tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update>
using ordered_multiset = tree <type1, null_type, less_equal <type1>, rb_tree_tag, tree_order_statistics_node_update>;
//ordered_multiset <ll> kek;(declaration for multiorder set)
// ordered_set o_set;(declaration)
//kek.order_of_key(i);(strictly less then i for multi order set)
//o_set.order_of_key(5) ;(strictly less then i for multi order set)
#define yes cout << "YES\n"
#define no cout << "NO\n"
#define mod 1000000007
class DSU
{
vector<ll>rank,parent;
public:
DSU(ll n)
{
rank.resize(n+1,0);
parent.resize(n+1);
for(ll i=0;i<=n;i++)
{
parent[i]=i;
}
}
ll findPar(ll node)
{
if(node==parent[node])
{
return parent[node]=node;
}
return parent[node]=findPar(parent[node]);
}
void unionByrank(ll u,ll v)
{
ll a=findPar(u);
ll b=findPar(v);
if(a==b)
{
return;
}
if(rank[a]<rank[b])
{
parent[a]=b;
}
else if(rank[a]>rank[b])
{
parent[b]=a;
}
else
{
parent[b]=a;
rank[a]+=1;
}
}
};
int main()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
ll n;
cin>>n;
DSU ds(n);
for(ll i=0;i<n-1;i++)
{
ll a,b;
cin>>a>>b;
ds.unionByrank(a,b);
}
if(ds.findPar(4)==ds.findPar(1))cout<<"YES\n";
else cout<<"NO\n";
return 0;
}
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