#include <bits/stdc++.h>
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>>;
unsigned int logceil(long long first) {
  return first ? 8 * sizeof(long long) - __builtin_clzll(first) : 0;
}
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.first) ^ (u(p.second) << 7);
  }
};
}  // namespace std
template <typename T, typename F>
T bsh(T l, T h, const F& f) {
  T r = -1, m;
  while (l <= h) {
    m = (l + h) / 2;
    if (f(m)) {
      l = m + 1;
      r = m;
    } else {
      h = m - 1;
    }
  }
  return r;
}
template <typename F>
double bshd(double l, double h, const F& f, double p = 1e-9) {
  unsigned int r = 3 + (unsigned int)log2((h - l) / p);
  while (r--) {
    double m = (l + h) / 2;
    if (f(m)) {
      l = m;
    } else {
      h = m;
    }
  }
  return (l + h) / 2;
}
template <typename T, typename F>
T bsl(T l, T h, const F& f) {
  T r = -1, m;
  while (l <= h) {
    m = (l + h) / 2;
    if (f(m)) {
      h = m - 1;
      r = m;
    } else {
      l = m + 1;
    }
  }
  return r;
}
template <typename F>
double bsld(double l, double h, const F& f, double p = 1e-9) {
  unsigned int r = 3 + (unsigned int)log2((h - l) / p);
  while (r--) {
    double m = (l + h) / 2;
    if (f(m)) {
      h = m;
    } else {
      l = m;
    }
  }
  return (l + h) / 2;
}
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)) {}
};
class A2AddOnATreeRevolution {
 public:
  int N, L;
  vector<vector<std::pair<int, int>>> E;
  vector<vector<int>> Ans;
  map<std::pair<int, int>, int> X;
  bool fail;
  void put(int a, int b, int c) { X[{min(a, b), max(a, b)}] += c; }
  int get(int a, int b) { return X[{min(a, b), max(a, b)}]; }
  void add(int a, int b, int first) {
    add(a, -1, b, first);
    Ans.push_back({a + 1, b + 1, first});
  }
  bool add(int u, int p, int b, int first) {
    if (u == b) return true;
    for (std::pair<int, int> v : E[u]) {
      if (v.first != p) {
        put(u, v.first, first);
        if (add(v.first, u, b, first)) return true;
        put(u, v.first, -first);
      }
    }
    return false;
  }
  int leaf(int u, int p) {
    if (E[u].size() == 1) {
      return u;
    }
    for (std::pair<int, int> v : E[u]) {
      if (v.first != p) return leaf(v.first, u);
    }
  }
  void process(int u, int v, int val) {
    if (val == 0) return;
    vector<int> Children;
    for (std::pair<int, int> w : E[v])
      if (w.first != u) Children.push_back(w.first);
    if (Children.size() == 0) {
      add(L, v, val);
    } else if (Children.size() == 1) {
      fail = true;
    } else {
      if (val % 2 == 1) {
        fail = true;
      } else {
        int l1 = leaf(Children[0], v);
        int l2 = leaf(Children[1], v);
        add(L, l1, val / 2);
        add(L, l2, val / 2);
        add(l1, l2, -val / 2);
      }
    }
  }
  void dfs(int u, int p) {
    for (std::pair<int, int> v : E[u]) {
      if (v.first != p) {
        dfs(v.first, u);
        process(u, v.first, v.second - get(u, v.first));
      }
    }
  }
  void solve(istream& cin, ostream& cout) {
    cin >> N;
    E.resize(N);
    for (int i = 0; i < N - 1; ++i) {
      int u, v, val;
      cin >> u >> v >> val;
      --u;
      --v;
      E[u].push_back({v, val});
      E[v].push_back({u, val});
    }
    L = 0;
    while (E[L].size() > 1) L++;
    fail = false;
    dfs(L, -1);
    if (fail) {
      cout << "NO\n";
    } else {
      cout << "YES\n" << Ans.size() << '\n';
      for (auto ans : Ans) cout << ans;
    }
  }
};
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(nullptr);
  cout.tie(nullptr);
  A2AddOnATreeRevolution solver;
  std::istream& in(std::cin);
  std::ostream& out(std::cout);
  solver.solve(in, out);
  return 0;
}
