#include <bits/stdc++.h>
using namespace std;
#define endl "\n"
#define int long long
#define pb push_back
#define ff first
#define ss second
#define mod 1000000007
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
const int N = 2e5 + 5;
int n;
vector<int> cnt(N),sum(N),vis(N);
vector<pair<int,int>> adj[N],val(N);
void dfs(int node,int p){
for(auto[go,who] : adj[node]){
if(go == p) continue;
dfs(go,node);
}
for(auto[go,who] : adj[node]){
if(go == p) continue;
cnt[who] = sum[go];
}
sum[node] += (node > 1) * (vis[node-1] ? -1 : 1);
sum[node] += (node < n) * (vis[node+1] ? -1 : 1);
}
void solve(){
cin >> n;
for(int i=1;i<n;i++){
int a,b; cin >> a >> b >> val[i].ff >> val[i].ss;
adj[a].pb({b,i});
adj[b].pb({a,i});
}
dfs(1,0);
int ans = 0;
for(int i=1;i<n;i++){
ans += min(cnt[i] * val[i].ff,val[i].ss);
}
cout << ans << endl;
}
signed main(){
ios::sync_with_stdio(0);
cin.tie(0);
int t = 1;
// cin >> t;
while(t--)
solve();
return 0;
}
