#include <bits/stdc++.h>
using namespace std;
struct debugger {
  template <typename T>
  debugger& operator,(const T& v) {
    std::cout << v << " ";
    return *this;
  }
} dbg;
template <typename T1, typename T2>
inline std::ostream& operator<<(std::ostream& os, const std::pair<T1, T2>& p) {
  return os << "(" << p.first << ", " << p.second << ")";
}
template <typename T>
inline std::ostream& operator<<(std::ostream& os, const std::vector<T>& v) {
  std::string delim = "[";
  for (unsigned int i = 0; i < v.size(); i++) {
    os << delim << v[i];
    delim = ", ";
  }
  return os << "]";
}
template <typename T>
inline std::ostream& operator<<(std::ostream& os, const std::set<T>& v) {
  std::string delim = "[";
  for (typename std::set<T>::const_iterator ii = v.begin(); ii != v.end();
       ++ii) {
    os << delim << *ii;
    delim = ", ";
  }
  return os << "]";
}
template <typename T1, typename T2>
inline std::ostream& operator<<(std::ostream& os, const std::map<T1, T2>& v) {
  std::string delim = "[";
  for (typename std::map<T1, T2>::const_iterator ii = v.begin(); ii != v.end();
       ++ii) {
    os << delim << *ii;
    delim = ", ";
  }
  return os << "]";
}
template <class T>
inline T bigmod(T a, T b, T M) {
  long long ret = 1;
  for (; b > 0; b >>= 1) {
    if (b & 1) ret = (ret * a) % M;
    a = (a * a) % M;
  }
  return (T)ret;
}
template <class T>
inline T gcd(T a, T b) {
  while (!b) {
    a = a % b;
    swap(a, b);
  }
  return a;
}
template <class T>
inline T lcm(T a, T b) {
  return (a / gcd(a, b)) * b;
}
template <class T>
inline T poww(T a, T b) {
  long long ret = 1;
  for (; b > 0; b >>= 1) {
    if (b & 1) ret = ret * a;
    a = a * a;
  }
  return (T)ret;
}
pair<int, int> exEuclid(int a, int b) {
  if (b == 0)
    return pair<int, int>(1, 0);
  else {
    pair<int, int> r = exEuclid(b, a % b);
    return pair<int, int>(r.second, r.first - r.second * (a / b));
  }
}
int modInv(int a, int m) {
  pair<int, int> ret = exEuclid(a, m);
  return ((ret.first % m) + m) % m;
}
int Set(int N, int pos) { return N = N | (1 << pos); }
int reset(int N, int pos) { return N = N & ~(1 << pos); }
bool check(int N, int pos) { return (bool)(N & (1 << pos)); }
struct edge {
  int from, to;
  long long w, p, delta;
  edge(int x, int y, int z, int m, int _del) {
    from = x;
    to = y;
    w = z;
    p = m;
    delta = _del;
  }
};
vector<edge> edges;
vector<int> g[200010];
int n, x, y, z, m;
bool ok = true;
long long sum[200010];
void dfs1(int u) {
  sum[u] = 0;
  for (int i = (0); i < (g[u].size()); i++) {
    int v = g[u][i];
    dfs1(edges[v].to);
    long long mi = min(edges[v].p - sum[edges[v].to], edges[v].w - 1);
    sum[u] += sum[edges[v].to];
    if (mi < 0) {
      ok = false;
      return;
    }
    edges[v].w -= mi;
    edges[v].p -= mi;
    edges[v].delta = mi;
    sum[u] += edges[v].w;
  }
  return;
}
long long dfs(int u, long long r) {
  long long spent = 0;
  for (int i = (0); i < (g[u].size()); i++) {
    int v = g[u][i];
    long long mi = min(r, edges[v].delta);
    edges[v].w += mi;
    edges[v].p += mi;
    r -= mi;
    long long ret = dfs(edges[v].to, min(r, edges[v].p - sum[edges[v].to]));
    spent += (ret + mi);
    r -= ret;
  }
  return spent;
}
int main() {
  cin >> n;
  for (int i = (1); i < (n); i++) {
    scanf("%d %d %d %d", &x, &y, &z, &m);
    edges.push_back(edge(x, y, z, m, 0));
    g[x].push_back(i - 1);
  }
  dfs1(1);
  if (!ok) {
    cout << -1 << endl;
    return 0;
  }
  dfs(1, 1e18);
  cout << n << endl;
  for (int i = (0); i < (edges.size()); i++) {
    cout << edges[i].from << " " << edges[i].to << " " << edges[i].w << " "
         << edges[i].p << endl;
  }
  return 0;
}
