#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define ALL(v) v.begin(), v.end()
typedef long long ll;

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

const int INF=1e9;

struct Edge{
  int to;
  int w;
  Edge(int to,ll w) : to(to),w(w) {}
};

using Graph=vector<vector<Edge>>;
using pli=pair<ll,int>;

int dist[100010];
int dim[100010];

template<class T> bool chmin(T& a,T b){
  if(a>b){
    a=b;
    return true;
  }
  return false;
}

int main(){
  int n;
  cin>>n;
  
  Graph G(n);
  rep(i,n-1){
    int a,b;
    cin>>a>>b;
    a--,b--;
    G[a].push_back(Edge(b,1));
    G[b].push_back(Edge(a,1));
  }
  
  rep(i,n) dim[i]=G[i].size();
  int cnt=0;
  int mid;
  rep(i,n){
    if(dim[i]>2){
      cnt++;
      mid=i;
    }
  }
  if(cnt>2){
    cout<<"No"<<endl;
    return 0;
  }
  else if(cnt==0){
    cout<<"Yes"<<endl;
    return 0;
  }

  int s=mid;
  rep(i,n) dist[i]=INF;
  dist[s]=0;
  
  priority_queue<pli,vector<pli>,greater<pli>> que;
  que.push({dist[s],s});
  
  while(!que.empty()){
    int v=que.top().second;
    ll d=que.top().first;
    que.pop();
    
    if(d>dist[v]) continue;
    
    for(auto e:G[v]){
      if(chmin(dist[e.to],dist[v]+e.w)){
        que.push({dist[e.to],e.to});
      }
    }
  }
  
  bool b=true;
  int tmp=-1;
  rep(i,n){
    if(dim[i]!=1) continue;
    if(tmp==-1) tmp=dist[i];
    else if(dist[i]!=tmp){
      b=false;
      break;
    }
  }
  if(b) cout<<"Yes"<<endl;
  else cout<<"No"<<endl;

  return 0;
}