#include <bits/stdc++.h>
#define vpii vector <pair <int, int>>
using namespace std;
using ll = int64_t;
const int N = 2e5 + 1, Log = 18;
int n;
int h[N];
int par[N][Log];
int price[N][2];
int rtail[N];
ll dif[N], ans;
vpii g[N];
void dfs(int v){
for(pair <int, int> &x: g[v]) if(x.first != par[v][0]){
int &u = x.first;
par[u][0] = v;
h[u] = h[v] + 1;
rtail[u] = x.second;
for(int i = 1; i < Log; ++i)
par[u][i] = par[par[u][i - 1]][i - 1];
dfs(u);
}
}
int getlca(int u, int v){
int dif = h[u] - h[v];
if(dif < 0){
dif = -dif;
u ^= v ^= u ^= v;
}
for(int i = 0; i < Log; ++i) if(dif >> i & 1) u = par[u][i];
if(u == v) return u;
for(int i = Log - 1; ~i; --i) if(par[u][i] != par[v][i])
u = par[u][i], v = par[v][i];
return par[u][0];
}
void dfssolve(int v){
for(pair <int, int> &x: g[v]) if(x.first != par[v][0]){
dfssolve(x.first);
dif[v] += dif[x.first];
}
if(v != 1)
ans += min(price[rtail[v]][0] * dif[v], (ll) price[rtail[v]][1]);
}
int main(){
ios::sync_with_stdio(false); cin.tie(nullptr);
cin >> n;
for(int u, v, i = 1; i < n; ++i){
cin >> u >> v >> price[i][0] >> price[i][1];
g[u].push_back({v, i});
g[v].push_back({u, i});
}
dfs(1);
for(int lca, u, v, i = 2; i <= n; ++i){
lca = getlca(i - 1, i);
u = i - 1, v = i;
if(h[u] > h[v]) u ^= v ^= u ^= v;
if(lca == u){
++dif[v];
--dif[u];
}else{
++dif[u]; ++dif[v];
dif[lca] -= 2;
}
}
dfssolve(1);
cout << ans;
cerr << "ok\n";
return 0;
}
