#include <bits/stdc++.h>
using namespace std;
vector<set<long long int>> G;
vector<set<long long int>> oriG;
int main() {
  cin.sync_with_stdio(false);
  cin.tie(0);
  long long int n;
  cin >> n;
  G.resize(n);
  for (long long int i = 0; i < n - 1; ++i) {
    long long int a, b;
    cin >> a >> b;
    --a;
    --b;
    G[a].insert(b);
    G[b].insert(a);
  }
  oriG = G;
  if (n == 1) {
    cout << "Yes\n";
    return 0;
  }
  for (long long int v = 0; v < n; ++v) {
    if (G[v].size() == 2) {
      auto it = G[v].begin();
      long long int a = *it;
      ++it;
      long long int b = *it;
      G[v].clear();
      G[a].erase(v);
      G[b].erase(v);
      G[a].insert(b);
      G[b].insert(a);
    }
  }
  for (long long int v = 0; v < n; ++v) {
    long long int cnt = 0;
    for (long long int x : G[v]) {
      if (G[x].size() >= 2) {
        if (G[x].size() == 3 && oriG[v].count(x)) {
          bool ok = true;
          for (long long int y : G[x]) {
            if (y == v) continue;
            if (G[y].size() != 1) ok = false;
          }
          if (ok) continue;
        }
        ++cnt;
      }
    }
    if (cnt >= 3) {
      cout << "No\n";
      return 0;
    }
  }
  cout << "Yes\n";
  return 0;
}
