// "Say:He is the Most Merciful,We have believed in him and upon him we have relied" [67:29]
//#pragma GCC optimize ("Ofast")
//#pragma GCC target ("avx2")
//#pragma GCC optimize("unroll-loops")
#include<bits/stdc++.h>
using namespace std;
/*
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
template<typename T>
using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
*/
typedef long long ll;
typedef long double ld;
typedef pair<ll,ll> pll;
typedef pair<int,int> pii;
typedef vector<ll> vll;
typedef vector<int> vii;
typedef map<int,int> mpi;
typedef map<ll,ll> mpl;
typedef unordered_map<int,int> umpi;
typedef unordered_map<ll,ll> umpl;
#define ump unordered_map
#define mod 1000000007
#define inf 1000000000000000006
#define infi 1000000009
#define ff first
#define ss second
#define pb push_back
#define all(v) v.begin(), v.end()
#define fastio ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL)
#define endl '\n'
#define pi acos(-1.0)
#define dec(n) fixed << setprecision(n)
#define N 200005
#define int long long
inline void IO(string name) { // Usaco
freopen((name + ".in").c_str(), "r", stdin);
freopen((name + ".out").c_str(), "w", stdout);
}
struct edge{
int u,v,c1,c2;
};
int n,par[N],con[N],lvl[N];
vector<edge> e;
vii g[N];
map<pii,int> mp;
struct lca{
int anc[N][25];
void init(int par[],int n){
memset(anc,-1,sizeof anc);
for(int i=1;i<=n;i++) anc[i][0]=par[i];
for(int j=1;(1<<j)<n;j++){
for(int i=1;i<=n;i++){
if(anc[i][j-1]!=-1) anc[i][j]=anc[anc[i][j-1]][j-1];
}
}
}
int findlca(int p,int q,int n){
int log;
if (lvl[p]<lvl[q]) swap(p,q);
log=1;
while(1){
int nxt=log+1;
if((1<<nxt)>lvl[p])break;
log++;
}
for(int i=log;i>=0;i--) if(lvl[p]-(1<<i)>=lvl[q]) p=anc[p][i];
if(p==q) return p;
for (int i=log;i>=0;i--){
if(anc[p][i]!=-1 && anc[p][i]!=anc[q][i]) p=anc[p][i],q=anc[q][i];
}
return par[p];
}
}khela;
void mdfs(int s,int p){
par[s]=p;
lvl[s]=lvl[p]+1;
for(auto dd:g[s]){
if(dd==p) continue;
mdfs(dd,s);
}
}
ll dfs(int s,int p){
ll val=0;
for(auto dd:g[s]){
if(dd==p) continue;
ll momo=dfs(dd,s);
mp[{s,dd}]+=momo;
mp[{dd,s}]+=momo;
val+=momo;
}
return val+con[s];
}
void solve(){
cin >> n;
e.resize(n-1);
for(int i=0;i<n-1;i++){
cin >> e[i].u >> e[i].v >> e[i].c1 >> e[i].c2;
g[e[i].u].pb(e[i].v);
g[e[i].v].pb(e[i].u);
}
lvl[0]=-1;
mdfs(1,0);
khela.init(par,n);
for(int i=1;i<n;i++){
con[i]++;
con[i+1]++;
con[khela.findlca(i,i+1,n)]-=2;
}
int xxx=dfs(1,0);
ll cost=0;
for(edge xx:e){
ll cnt=mp[{xx.u,xx.v}];
cost+=min(cnt*xx.c1,xx.c2);
}
cout << cost << endl;
}
signed main(){
fastio;
//srand(chrono::steady_clock::now().time_since_epoch().count());
int T=1,cs=0;
//cin >> T;
while(T--){
//cout << "Case " << ++cs << ":" << " " ;
solve();
}
}
