#include <bits/stdc++.h>
using namespace std;
using ld = long double;
using ull = unsigned long long;
/*
#pragma comment(linker, "/STACK:256000000")
#pragma GCC optimize("unroll-loops")
#pragma GCC optimize("Ofast")
#pragma GCC optimize("-O3")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
*/
template <class T> inline T gcd(T a , T b) { return !a ? b : gcd(b % a , a); }
template <class T> inline T lcm(T a , T b) { return (a * b) / gcd(a , b) ; }
mt19937 rnd(time(0));
#define all(x) x.begin(), x.end()
#define debug(x) { cerr << #x << " = " << x << endl; }
const int N = 2e5 + 2;
const int LOG = 20;
int timer = 0, tin[N], tout[N], prefix[N], dp[N];
vector<vector<pair<int, int>>> g(N, vector<pair<int, int>>());
vector<vector<int>> up(N, vector<int>(LOG, 1));
void dfs1(int v, int p = 1) {
tin[v] = timer++;
up[v][0] = p;
for (int i = 1; i < LOG; i++) {
up[v][i] = up[up[v][i - 1]][i - 1];
}
for (auto edge : g[v]) {
int to = edge.first;
if (to != p) {
dfs1(to, v);
}
}
tout[v] = timer++;
}
bool ancestor(int a, int b) {
return (tin[a] <= tin[b] && tout[a] >= tout[b]);
}
int lca(int a, int b) {
if (ancestor(a, b)) {
return a;
}
if (ancestor(b, a)) {
return b;
}
for (int i = LOG - 1; i >= 0; i--) {
if (!ancestor(up[a][i], b)) {
a = up[a][i];
}
}
return up[a][0];
}
void dfs2(int v, int p = -1, int in = -1) {
for (auto edge : g[v]) {
int to = edge.first, num = edge.second;
if (to != p) {
dfs2(to, v, num);
prefix[v] += prefix[to];
}
}
if (in != -1) {
dp[in] = prefix[v];
}
}
void solve() {
int n;
cin >> n;
vector<int> cost1(n), cost2(n);
for (int i = 1; i < n; i++) {
int u, v;
cin >> u >> v >> cost1[i] >> cost2[i];
g[u].push_back({v, i});
g[v].push_back({u, i});
}
dfs1(1);
for (int i = 1; i < n; i++) {
prefix[i]++;
prefix[i + 1]++;
prefix[lca(i, i + 1)] -= 2;
}
dfs2(1);
long long ans = 0ll;
for (int i = 1; i < n; i++) {
ans += min(1ll * cost2[i], cost1[i] * 1ll * dp[i]);
}
cout << ans << '\n';
return;
}
signed main() {
ios_base :: sync_with_stdio(0);
cin.tie(0) , cout.tie(0);
int t = 1;
while (t-- > 0) {
solve();
}
return 0;
}
