#include <bits/stdc++.h>
using namespace std;
const int N = 1e5 + 5;
int n, root;
vector<int> adj[N];
bool ok;
int dfs(int v, int p = -1) {
  int ret = 0;
  int cnt = 2;
  if (v == root) cnt++;
  for (int u : adj[v]) {
    if (u == p) continue;
    int res = dfs(u, v);
    if (res) ret = 2;
    if (res == 2) cnt--;
  }
  if (cnt <= 0) {
    ok = false;
  }
  if (adj[v].size() == 3) ret = max(1, ret);
  if (adj[v].size() > 3) ret = 2;
  return ret;
}
int main() {
  scanf("%d", &n);
  for (int i = 1; i < n; i++) {
    int a, b;
    scanf("%d%d", &a, &b);
    a--;
    b--;
    adj[a].push_back(b);
    adj[b].push_back(a);
  }
  ok = true;
  root = 0;
  for (int i = 0; i < n; i++)
    if (adj[root].size() < adj[i].size()) root = i;
  dfs(root);
  if (!ok && adj[root].size() == 3) {
    ok = true;
    for (int u : adj[root]) {
      if (adj[u].size() == 3) {
        root = u;
        break;
      }
    }
    dfs(root);
  }
  if (ok)
    puts("Yes");
  else
    puts("No");
  return 0;
}
