#include <bits/stdc++.h>
using namespace std;
long long int n, val[1003][1003], deg[1003] = {0}, v1, v2;
vector<long long int> g[2005], v, vx, x;
vector<pair<long long int, long long int>> fin;
long long int dfs1(long long int node, long long int p = -1);
vector<long long int> dfs(long long int node, long long int p1 = -1) {
  x.clear();
  for (auto y : g[node]) {
    if (y == p1) continue;
    x.push_back(y);
  }
  vx.clear();
  v.clear();
  long long int v1 = dfs1(x[0], node);
  v.clear();
  long long int v2 = dfs1(x[1], node);
  vx.push_back(v1);
  vx.push_back(v2);
  return vx;
}
long long int dfs1(long long int node, long long int p) {
  if (deg[node] == 1) return node;
  for (auto y : g[node]) {
    if (y == p) continue;
    long long int exel = dfs1(y, node);
    if (exel != 0) return exel;
  }
  return 0;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  long long int i, j, k, x;
  cin >> n;
  for (long long int i = 0; i <= n - 2; i++) {
    cin >> j >> k >> x;
    val[j][k] = x;
    val[k][j] = x;
    g[j].push_back(k);
    g[k].push_back(j);
    fin.push_back(make_pair(j, k));
    deg[j]++;
    deg[k]++;
  }
  for (long long int i = 0; i <= n; i++)
    if (deg[i] == 2) {
      cout << "NO";
      return 0;
    }
  cout << "YES\n";
  vector<pair<pair<long long int, long long int>, long long int>> ans;
  for (auto y : fin) {
    v.clear();
    k = val[y.first][y.second];
    if (deg[y.first] == 1 && deg[y.second] == 1) {
      ans.push_back(make_pair(make_pair(y.first, y.second), k));
    } else if (deg[y.first] == 1) {
      vector<long long int> wex = dfs(y.second, y.first);
      ans.push_back(make_pair(make_pair(y.first, wex[0]), k / 2));
      ans.push_back(make_pair(make_pair(y.first, wex[1]), k / 2));
      ans.push_back(make_pair(make_pair(wex[1], wex[0]), -k / 2));
    } else if (deg[y.second] == 1) {
      vector<long long int> hex = dfs(y.first, y.second);
      ans.push_back(make_pair(make_pair(y.second, hex[0]), k / 2));
      ans.push_back(make_pair(make_pair(y.second, hex[1]), k / 2));
      ans.push_back(make_pair(make_pair(hex[1], hex[0]), -k / 2));
    } else {
      vector<long long int> hex = dfs(y.first, y.second);
      v.clear();
      vector<long long int> wex = dfs(y.second, y.first);
      ans.push_back(make_pair(make_pair(hex[0], hex[1]), -k / 2));
      ans.push_back(make_pair(make_pair(wex[0], wex[1]), -k / 2));
      ans.push_back(make_pair(make_pair(hex[0], wex[0]), k / 2));
      ans.push_back(make_pair(make_pair(hex[1], wex[1]), k / 2));
    }
  }
  cout << ans.size() << "\n";
  for (auto y : ans)
    cout << y.first.first << " " << y.first.second << " " << y.second << '\n';
  return 0;
}
