#include <bits/stdc++.h>
#define x first
#define y second
using namespace std;
using ll=long long;
using pii=pair<int,int>;
using vi=vector<int>;
using vl=vector<ll>;
#define pb push_back
#define all(a) begin(a),end(a)

const int N=300010,MOD=1e9+7;
const char en='\n';
const ll LLINF=1ll<<60;

int n,cn[N];
set<int> ch[N];
set<pii> s;

int main()
{
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	cin>>n;
	for (int i=1;i<=n;++i)
	{
		if (i<n)
		{
			int a,b;
			cin>>a>>b;
			ch[a].insert(b);
			ch[b].insert(a);
		}
		cn[i]=1;
	}
	for (int i=1;i<=n;++i) if (ch[i].size()==1) s.insert({cn[i],i});
	for (int z=0;z<n-2;++z)
	{
		int i=s.begin()->y;
		s.erase(s.begin());
		int u=*ch[i].begin();
		if (cn[u]<cn[i])
		{
			cout<<"NO\n";
			exit(0);
		}
		cn[u]+=cn[i];
		ch[u].erase(i);
		if (ch[u].size()==1) s.insert({cn[u],u});
	}
	cout<<"YES\n";
}