#include <bits/stdc++.h>
using namespace std;
#define all(x) x.begin(), x.end()
const int N = 2e5 + 2;
const int LOG = 19;
int L = 1 , timer = 0;
int tin[N] , tout[N] , c[N] , d[N];
int up[N][LOG] , cnt[N] , p[N] , dp[N];
vector<vector<pair<int , int> > > g(N , vector<pair<int , int> >());
void dfs1(int v , int p = 1) {
tin[v] = ++timer;
up[v][0] = p;
for (int i = 1; i <= L; i++) {
up[v][i] = up[up[v][i - 1]][i - 1];
}
for (auto e : g[v]) {
int to = e.first;
int pos = e.second;
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 = L; i >= 0; --i) {
if (!ancestor(up[a][i] , b)) {
a = up[a][i];
}
}
return up[a][0];
}
void dfs(int v , int par = -1 , int in = -1) {
for (auto e : g[v]) {
int to = e.first;
int edgeNum = e.second;
if (to != par) {
dfs(to , v , edgeNum);
dp[v] += dp[to];
}
}
dp[v] += p[v];
if (in != -1) {
cnt[in] = dp[v];
}
}
int main() {
#ifdef judge
ifstream cin("input.txt");
#endif // judge
ios_base :: sync_with_stdio(0);
cin.tie(0) , cout.tie(0);
int n;
cin >> n;
while ((1 << L) <= n) {
L++;
}
for (int i = 0; i < n - 1; i++) {
int u , v;
cin >> u >> v >> c[i] >> d[i];
g[u].push_back({v , i});
g[v].push_back({u , i});
}
dfs1(1);
for (int i = 1; i < n; i++) {
int anc = lca(i , i + 1);
p[i]++ , p[i + 1]++;
p[anc] -= 2;
}
dfs(1 , -1);
long long ans = 0LL;
for (int i = 0; i < n - 1; i++) {
ans += min(c[i] * 1LL * cnt[i] , 1LL * d[i]);
}
cout << ans << '\n';
return 0;
}
