#include <bits/stdc++.h>
using namespace std;
const int N = 1e5 + 5;
int ds = 0;
vector<int> adj[N];
int lvs[N], sz[N], dep[N];
vector<int> twos[N];
int dfs(int v, int p, int n) {
  sz[v] = 1;
  dep[v] = dep[p] + 1;
  int mxd = 0;
  lvs[v] = (adj[v].size() == 1);
  for (auto it : adj[v]) {
    if (it == p) continue;
    int d = dfs(it, v, n);
    lvs[v] += lvs[it];
    if (lvs[it] > 2 or (lvs[it] == 2 and (int) adj[it].size() < 3))
      twos[v].push_back(it);
    sz[v] += sz[it];
    mxd = max(mxd, d);
  }
  if (ds - lvs[v] > 2 or (ds - lvs[v] == 2 and (int) adj[p].size() < 3)) {
    twos[v].push_back(p);
  }
  return mxd + 1;
}
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  int n;
  cin >> n;
  for (int i = 1; i < n; i++) {
    int a, b;
    cin >> a >> b;
    adj[a].push_back(b), adj[b].push_back(a);
  }
  for (int i = 1; i <= n; i++) {
    if ((int)adj[i].size() == 1) ds++;
  }
  dfs(1, 0, n);
  for (int i = 1; i <= n; i++) {
    if ((int)twos[i].size() > 2) {
      cout << "No\n";
      exit(0);
    }
  }
  cout << "Yes\n";
  return 0;
}
