#include<iostream>
#include<vector>
#include<queue>
using namespace std;
int N;
vector<int>G[1<<17];
int dist[1<<17];
main()
{
	cin>>N;
	for(int i=1;i<N;i++)
	{
		int a,b;cin>>a>>b;a--,b--;
		G[a].push_back(b);
		G[b].push_back(a);
	}
	int id=0;
	while(id<N&&G[id].size()<=2)id++;
	if(id==N)
	{
		cout<<"Yes"<<endl;
		return 0;
	}
	for(int i=id+1;i<N;i++)if(G[i].size()>2)
	{
		cout<<"No"<<endl;
		return 0;
	}
	queue<int>P;P.push(id);
	for(int i=0;i<N;i++)dist[i]=1e9;
	dist[id]=0;
	while(!P.empty())
	{
		int u=P.front();P.pop();
		for(int v:G[u])if(dist[v]>dist[u]+1)
		{
			dist[v]=dist[u]+1;
			P.push(v);
		}
	}
	int mx=-1;
	for(int i=0;i<N;i++)if(G[i].size()==1)
	{
		if(mx==-1)mx=dist[i];
		else if(mx!=dist[i])
		{
			cout<<"No"<<endl;
			return 0;
		}
	}
	cout<<"Yes"<<endl;
}