#include <bits/stdc++.h>
using namespace std;
template <typename T>
using min_queue = priority_queue<T, vector<T>, greater<T>>;
const long long MOD = 1e9 + 7;
vector<int> g[1010];
long long edg[1010][1010];
map<pair<int, int>, long long> res;
int leaf[1010];
int N;
void dfs(int v, int p) {
  leaf[v] = v;
  for (int w : g[v]) {
    if (w == p) continue;
    dfs(w, v);
    leaf[v] = leaf[w];
  }
}
bool dfs3(int v, int l2, int p, long long r) {
  if (v == l2) return 1;
  for (int w : g[v]) {
    if (w == p) continue;
    if (dfs3(w, l2, v, r)) {
      edg[v][w] += r;
      edg[w][v] += r;
      return 1;
    }
  }
  return 0;
}
void add(int l1, int l2, long long r) {
  if (r == 0) return;
  if (l1 > l2) swap(l1, l2);
  res[{l1, l2}] += r;
  dfs3(l1, l2, 0, -r);
}
void dfs2(int v, int p, long long r, int l1, int l2) {
  add(leaf[v], l1, r / 2);
  add(leaf[v], l2, r / 2);
  add(l1, l2, -r / 2);
  vector<int> ww;
  for (int w : g[v]) {
    if (w != p) ww.push_back(w);
  }
  for (int w : g[v]) {
    long long r = edg[v][w];
    if (w == p) continue;
    if (ww.size() > 1) {
      if (ww[0] == w)
        l2 = leaf[ww[1]];
      else
        l2 = leaf[ww[0]];
    }
    dfs2(w, v, r, l1, l2);
  }
}
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cin >> N;
  for (int i = 0; i < N - 1; i++) {
    int a, b;
    cin >> a >> b;
    long long val;
    cin >> val;
    g[a].push_back(b);
    g[b].push_back(a);
    edg[a][b] = edg[b][a] = val;
  }
  bool good = 1;
  int rt = 0;
  for (int i = 1; i <= N; i++) {
    if (g[i].size() != 2) {
      if (rt == 0 || g[i].size() >= 3) rt = i;
      continue;
    }
    if (edg[i][g[i][0]] != edg[i][g[i][1]]) {
      good = 0;
      break;
    }
  }
  if (!good) {
    cout << "NO\n";
    return 0;
  }
  cout << "YES\n";
  dfs(rt, 0);
  if (g[rt].size() == 1) {
    long long v = edg[rt][g[rt][0]];
    cout << 1 << endl;
    cout << rt << ' ' << leaf[rt] << ' ' << v << endl;
    return 0;
  }
  set<int> ch;
  for (int w : g[rt]) {
    if (ch.size() >= 3) break;
    ch.insert(w);
  }
  for (int w : g[rt]) {
    set<int> ch1 = ch;
    ch1.erase(w);
    int l1 = leaf[*ch1.begin()];
    int l2 = leaf[*ch1.rbegin()];
    dfs2(w, rt, edg[rt][w], l1, l2);
  }
  int cnt = 0;
  for (auto pr : res)
    if (pr.second != 0 && pr.first.first != pr.first.second) cnt++;
  cout << cnt << '\n';
  for (auto pr : res) {
    if (pr.second != 0 && pr.first.first != pr.first.second)
      cout << pr.first.first << ' ' << pr.first.second << ' ' << pr.second
           << endl;
  }
  return 0;
}
