#include <bits/stdc++.h>
using namespace std;
using namespace std;
template <typename T, typename U>
std::istream& operator>>(std::istream& i, pair<T, U>& p) {
  i >> p.first >> p.second;
  return i;
}
template <typename T>
std::istream& operator>>(std::istream& i, vector<T>& t) {
  for (auto& v : t) {
    i >> v;
  }
  return i;
}
template <typename T, typename U>
std::ostream& operator<<(std::ostream& o, const pair<T, U>& p) {
  o << p.first << ' ' << p.second;
  return o;
}
template <typename T>
std::ostream& operator<<(std::ostream& o, const vector<T>& t) {
  if (t.empty()) o << '\n';
  for (size_t i = 0; i < t.size(); ++i) {
    o << t[i] << " \n"[i == t.size() - 1];
  }
  return o;
}
template <typename T>
using minheap = priority_queue<T, vector<T>, greater<T>>;
template <typename T>
using maxheap = priority_queue<T, vector<T>, less<T>>;
template <typename T>
bool in(T a, T b, T c) {
  return a <= b && b < c;
}
unsigned int logceil(int x) {
  return (unsigned int)(8 * sizeof(int) - __builtin_clz(x));
}
namespace std {
template <typename T, typename U>
struct hash<pair<T, U>> {
  hash<T> t;
  hash<U> u;
  size_t operator()(const pair<T, U>& p) const {
    return t(p.x) ^ (u(p.y) << 7);
  }
};
}  // namespace std
template <typename T>
T gcd(T a, T b) {
  if (a < b) swap(a, b);
  return b ? gcd(b, a % b) : a;
}
template <typename T>
class vector2 : public vector<vector<T>> {
 public:
  vector2() {}
  vector2(size_t a, size_t b, T t = T())
      : vector<vector<T>>(a, vector<T>(b, t)) {}
};
template <typename T>
class vector3 : public vector<vector2<T>> {
 public:
  vector3() {}
  vector3(size_t a, size_t b, size_t c, T t = T())
      : vector<vector2<T>>(a, vector2<T>(b, c, t)) {}
};
template <typename T>
class vector4 : public vector<vector3<T>> {
 public:
  vector4() {}
  vector4(size_t a, size_t b, size_t c, size_t d, T t = T())
      : vector<vector3<T>>(a, vector3<T>(b, c, d, t)) {}
};
template <typename T>
class vector5 : public vector<vector4<T>> {
 public:
  vector5() {}
  vector5(size_t a, size_t b, size_t c, size_t d, size_t e, T t = T())
      : vector<vector4<T>>(a, vector4<T>(b, c, d, e, t)) {}
};
void fastIO() { ios::sync_with_stdio(false); }
template <typename T, typename... Args>
T max(T t, Args... args) {
  return max(max<T>(args...), t);
}
template <typename T, typename... Args>
T min(T t, Args... args) {
  return min(min<T>(args...), t);
}
vector<vector<int>> g;
vector<map<int, vector<int>>> f;
vector<int> findC(int v, int p) {
  if (f[v].count(p)) return f[v][p];
  if (g[v].size() == 1) {
    return {v};
  }
  auto& ans = f[v][p];
  for (auto nv : g[v]) {
    if (nv == p) continue;
    auto x = findC(nv, v);
    ans.push_back(x[0]);
    if (ans.size() == 2) return ans;
  }
  return ans;
}
vector<pair<pair<int, int>, int>> edges;
pair<int, int> getC(int v, int p) {
  if (g[v].size() == 1) return {v, v};
  auto tans = findC(v, p);
  if (tans.size() < 2) return {-1, -1};
  return {tans[0], tans[1]};
}
class A2PribavlenieNaDereveRevolyuciya {
 public:
  void solve(std::istream& in, std::ostream& out) {
    fastIO();
    int n;
    in >> n;
    g.clear();
    g.resize(n);
    f.clear();
    f.resize(n);
    for (int i = 0; i < n - 1; ++i) {
      int a, b, c;
      in >> a >> b >> c;
      --a;
      --b;
      g[a].push_back(b);
      g[b].push_back(a);
      edges.push_back({{a, b}, c});
    }
    vector<pair<pair<int, int>, int>> ans;
    for (auto e : edges) {
      int a = e.first.first;
      int b = e.first.second;
      int c = e.second;
      if (c == 0) continue;
      auto v1 = getC(a, b);
      auto v2 = getC(b, a);
      if (v1.first == -1 || v2.first == -1) {
        out << "NO" << endl;
        return;
      }
      ans.push_back({{v1.first, v2.first}, c / 2});
      ans.push_back({{v1.second, v2.second}, c / 2});
      if (v1.first != v1.second) ans.push_back({{v1.first, v1.second}, -c / 2});
      if (v2.first != v2.second) ans.push_back({{v2.first, v2.second}, -c / 2});
    }
    out << "YES" << endl;
    out << ans.size() << endl;
    for (auto p : ans) {
      out << p.first.first + 1 << " " << p.first.second + 1 << " " << p.second
          << endl;
    }
  }
};
int main() {
  A2PribavlenieNaDereveRevolyuciya solver;
  std::istream& in(std::cin);
  std::ostream& out(std::cout);
  solver.solve(in, out);
  return 0;
}
