#include <atcoder/all>
#include <bits/stdc++.h>
using namespace std;
using ll=long long;
using ull=unsigned long long;
#define rep(i,n) for(int i=0; i<(n); i++)
using mll=atcoder::static_modint<1000000007>;

int N;
vector<vector<int>> E;
vector<int> D;

int main(){
  scanf("%d",&N);
  E.resize(N);
  rep(i,N-1){
    int u,v; scanf("%d%d",&u,&v); u--; v--;
    E[u].push_back(v);
    E[v].push_back(u);
  }
  queue<int> Q;
  D.assign(N,-1);
  rep(i,N) if(E[i].size()==1){ D[i]=0; Q.push(i); }
  while(Q.size()){
    int p=Q.front(); Q.pop();
    for(int e:E[p]) if(D[e]==-1){ D[e]=D[p]+1; Q.push(e); }
  }
  int maxD=0; rep(i,N) maxD=max(maxD,D[i]);
  bool ok=true;
  int centEdge=0;
  rep(p,N){
    int X[3]={};
    for(int e:E[p]){
      int dD=abs(D[e]-D[p]);
      if(dD==1) continue;
      if(dD==0){ centEdge++; continue; }
      printf("No\n"); return 0;
    }
  }
  if(centEdge>2){ printf("No\n"); return 0; }
  printf("Yes\n");
  return 0;
}