#include <bits/stdc++.h>
using namespace std;
typedef long long LL;
constexpr int NMAX = 2e5 + 5;
struct Edge {
int X, Y;
int Cost_1, Cost_2;
};
int N;
vector <int> G[NMAX];
Edge E[NMAX];
int fr[NMAX];
int Level[NMAX];
int Dad[18][NMAX];
int Add[NMAX];
void Read () {
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
cin >> N;
for (int i = 1; i < N; ++ i ) {
cin >> E[i].X >> E[i].Y >> E[i].Cost_1 >> E[i].Cost_2;
G[E[i].X].push_back(i);
G[E[i].Y].push_back(i);
}
}
void Dfs (int Node, int dad = 0) {
Dad[0][Node] = dad;
Level[Node] = Level[dad] + 1;
for (int i = 1; i < 18; ++ i )
Dad[i][Node] = Dad[i-1][Dad[i-1][Node]];
for (auto it : G[Node]) {
int to = (E[it].X == Node ? E[it].Y : E[it].X);
if (to == dad) continue;
Dfs(to, Node);
}
}
int Parent (int Node, int who) {
for (int i = 0; i < 18; ++ i )
if ((who&(1<<i))) Node = Dad[i][Node];
return Node;
}
int LCA (int x, int y) {
if (Level[x] > Level[y]) swap(x, y);
y = Parent(y, Level[y] - Level[x]);
if (x == y) return x;
for (int i = 17; i >= 0; -- i ) {
if (Dad[i][x] != Dad[i][y]) {
x = Dad[i][x];
y = Dad[i][y];
}
}
return Dad[0][x];
}
void Precalculare () {
Dfs(1);
for (int i = 1; i < N; ++ i ) {
int z = LCA(i, i+1);
Add[i]++;
Add[i+1]++;
Add[z] -= 2;
}
}
void Collect (int Node, int dad = -1, int ind = 0) {
for (auto it : G[Node]) {
int to = (E[it].X == Node ? E[it].Y : E[it].X);
if (to == dad) continue;
Collect(to, Node, it);
Add[Node] += Add[to];
}
fr[ind] = Add[Node];
}
void Solve () {
Collect(1);
LL ans = 0;
for (int i = 1; i < N; ++ i )
ans += min(1LL * E[i].Cost_2, 1LL * fr[i] * E[i].Cost_1);
cout << ans << '\n';
}
int main()
{
Read();
Precalculare();
Solve();
return 0;
}
